Low Back Pain Causes: Why Does My Back Hurt?

Low back pain causes can include muscle strain, sudden increases in physical activity, irritated spinal joints, discs or nerves. However, most low back pain is non-specific, meaning there isn’t one identifiable injury or structural problem responsible for the pain.

If you’ve ever felt a sudden catch in your lower back while bending over to lift something off the floor, or felt stiff and sore after getting back into exercise, you are certainly not alone. Low back pain is one of the most common reasons patients come to see us at Lilyfield Physiotherapy.

Understanding why back pain happens, what common movement patterns can aggravate it, and how your nervous system plays a role is the first step towards managing your symptoms and moving comfortably again.

Quick summary

• Most low back pain is non-specific: Around 90% of cases have no single identifiable structural cause.
• Common physical causes: Muscle strain, sudden increases in physical load, disc irritation, nerve irritation and spinal joint conditions.
• Everyday triggers: Prolonged sitting, repetitive lifting, returning to exercise and doing more activity than your body is accustomed to.
• Other contributing factors: Stress, poor sleep, reduced physical activity and previous episodes of back pain can influence symptoms.
• Scans aren’t always necessary: X-rays and MRIs are not routinely recommended for low back pain unless an assessment identifies a reason for further investigation.
• Movement matters: Staying appropriately active and gradually rebuilding strength are common parts of low back pain management.

What Are the Most Common Causes of Low Back Pain?

Low back pain can come from several structures around your lower spine, including muscles, ligaments, joints, discs and nerves.

However, feeling pain in a particular area doesn’t necessarily mean that something is damaged there.

1. Non-Specific Low Back Pain

Non-specific low back pain is the most common type of back pain.

According to the World Health Organization, approximately 90% of low back pain cases are non-specific. This means no single disease or structural problem can confidently explain the symptoms.

Instead, pain may be influenced by a combination of factors, including physical activity, tissue sensitivity, muscle capacity, previous injuries, stress and sleep.

For example, you might experience back pain after a long day sitting at work, followed by gardening or lifting something heavy. There may not be one damaged structure responsible. Instead, your back may be responding to several physical and lifestyle demands.

Non-specific doesn’t mean your pain isn’t real. It simply means that identifying one exact structure as the cause isn’t always possible or necessary.

2. Muscle Strain and Overload

Muscle strains and sudden increases in physical load are common contributors to low back pain.

Your lower back contains muscles and connective tissues that support your spine during bending, lifting, twisting and everyday movement.

Pain can develop when these tissues are exposed to demands they’re not accustomed to, particularly after a period of reduced activity.

Common examples include:

• Lifting a heavy object awkwardly or unexpectedly.
• Returning to running, gym training or sport after a break.
• Repeated bending and lifting while gardening or cleaning.
• Increasing exercise intensity or duration too quickly.

This doesn’t mean bending or lifting is inherently dangerous. Your back is designed to move and manage load. The key is building the strength and physical capacity needed for the activities you want to do.

3. Disc Irritation and Sciatica

The discs between your spinal bones help absorb and distribute forces as you move.

Sometimes, changes to a spinal disc can contribute to pain, particularly when nearby nerves become irritated.

A disc that presses on or irritates a nerve may cause sciatica, which can involve pain travelling from the lower back or buttock into the leg. Some people also experience tingling, numbness or weakness.

However, disc bulges and other changes are common in people who have no back pain at all.

Finding a disc bulge on an MRI doesn’t automatically mean it is causing your symptoms.

4. Spinal Joint Changes and Arthritis

Your spine contains small joints that allow you to bend, twist and move comfortably.

Like other joints in the body, these can change with age. Conditions such as osteoarthritis may contribute to back pain and stiffness in some people.

However, age-related changes don’t always cause symptoms. Many people have visible joint changes on scans without experiencing pain.

Your physiotherapist will consider your symptoms, movement and medical history rather than relying on imaging findings alone.

5. Less Common Medical Causes

Although most low back pain isn’t caused by a serious condition, some cases have a more specific medical explanation.

These can include:

• Spinal fractures: Particularly following an injury or in people with osteoporosis.
• Inflammatory conditions: Such as axial spondyloarthritis, which can cause ongoing back pain and stiffness.
• Kidney problems: Kidney stones or infections can sometimes cause pain around the lower back or side.
• Spinal infections or tumours: Uncommon causes that require medical assessment.

These conditions may have additional symptoms beyond ordinary back pain. We’ll cover the warning signs that need medical attention further below.

Common Daily Activities That Trigger Low Back Pain

Back pain can sometimes seem to occur out of nowhere. In many cases, however, your daily activities, recent changes in movement and physical capacity can help explain why symptoms have appeared.

Some of the most common aggravators we see in clinic include:

The All-Day Desk Sitter

Hours spent sitting at a desk can leave your back and hips feeling stiff, particularly when you rarely change position.

Reduced movement through the mid-back (thoracic spine) and hips may also influence how you move during the day.

There isn’t one universally bad sitting posture. The bigger concern is often spending long periods in the same position without enough movement or variation.

The New Mum or Dad

Repeatedly bending, twisting and reaching to lift a growing baby out of a cot or pram places repetitive mechanical load on the lower back.

These demands are often amplified by interrupted sleep, fatigue and limited recovery time.

The Weekend Warrior

Returning to higher-intensity exercise, gardening or long walks after a period of lower physical activity can leave joints and muscles working harder than they’re accustomed to.

Your physical capacity may not yet match the demands of your activity.

When these movement patterns repeat without adequate variation or recovery, local tissues can become sensitive, guarded and painful.

Why Is My Back Pain Worse When I’m Stressed or Sleep-Deprived?

When back pain flares up, it’s easy to assume something has mechanically “slipped”, “displaced” or “broken”.

However, back pain is rarely purely mechanical.

Your nervous system acts like a volume knob for pain. When you’re running on poor sleep, feeling stressed at work or feeling anxious about your back, your body’s sensitivity to pain can increase.

Stress, fatigue and an overprotective nervous system can make everyday movements feel more uncomfortable or threatening.

This doesn’t mean your pain is imaginary or that stress is the only cause. It means your brain and nervous system influence how strongly pain is experienced.

For example, you might cope comfortably with a busy day of lifting or gardening when you’re well-rested, but find the same activities more painful after several nights of poor sleep.

Understanding these influences can help explain why back pain changes from day to day, even when your physical activities remain similar.

Who Is Most Likely to Experience Low Back Pain?

Back pain can affect anyone at any stage of life, but clinical data shows that the highest number of cases occurs among adults aged 50 to 55 years, with low back pain remaining common throughout later adulthood.

For adults in their 40s, 50s and 60s, symptoms may be influenced by changes in physical activity, cumulative work and family demands, previous episodes of pain and changes in tissue tolerance.

However, getting older doesn’t automatically mean you should expect ongoing back pain.

Maintaining physical activity, strength and confidence in movement can form part of a practical long-term approach to back health.

Do I Need a Scan for Low Back Pain?

When back pain strikes, it’s natural to feel like an X-ray or MRI is necessary to “see what’s wrong”.

However, clinical evidence shows that routine scans are rarely helpful for non-specific low back pain.

There are three main reasons:

• Scans show normal age-related changes: Just like getting grey hair or wrinkles on the outside, our spines undergo structural changes on the inside as we age. Many people without back pain have disc bulges, arthritis or degenerative changes on an MRI.
• Scan findings can create unnecessary fear: Seeing terms like “wear and tear”, “disc degeneration” or “disc bulge” can lead people to become overly protective of their backs, even when those findings aren’t responsible for their symptoms.
• Scans often don’t change the care plan: Unless specific warning signs or other clinical indications are present, imaging may not change the recommended first-line care, which usually focuses on staying active, understanding pain and rebuilding movement.

The Australian Low Back Pain Clinical Care Standard recommends reserving imaging for situations where there is concern about a serious underlying condition or another clear clinical reason.

Your physiotherapist or GP can assess whether further investigation is appropriate.

When Should I Worry About Low Back Pain?

Most episodes of low back pain aren’t caused by a serious medical condition.

However, certain symptoms require prompt medical assessment.

Seek emergency medical care if back pain is accompanied by new loss of bladder or bowel control, numbness around the groin or saddle area, or rapidly worsening leg weakness. These can indicate serious nerve compression.

You should also seek urgent medical advice if you have:

• Back pain following a significant fall or accident.
• Fever or feeling very unwell alongside back pain.
• Unexplained weight loss or a history of cancer with new back pain.
• New or worsening numbness, tingling or weakness in the legs.
• Severe or worsening pain, particularly when accompanied by other concerning symptoms.

If your pain isn’t improving, keeps returning or is interfering with sleep and daily activities, arrange an assessment with a healthcare professional.

How Can Physiotherapy Help With Low Back Pain?

If back pain is holding you back, you don’t have to manage it alone.

At Lilyfield Physiotherapy, our approach focuses on understanding your symptoms, identifying contributing factors and developing a practical plan around your daily activities and goals.

1. Understanding Your Pain Drivers

Our physiotherapists will ask about your symptoms, medical history, movement, lifestyle and recent changes in activity.

We’ll help you understand what may be contributing to your pain, explain the assessment findings and discuss any concerns you have about scans or previous diagnoses.

2. Restoring Confidence in Movement

When your back hurts, it’s understandable to become cautious about bending, lifting or exercising.

We’ll work with you to identify movements and activities that are appropriate for your current symptoms and help you approach them with greater confidence.

In many cases, comfortable and gradually progressed movement is an important part of managing low back pain.

3. Tailored Rehabilitation

Depending on your needs, your physiotherapy for back pain may combine hands-on treatment where appropriate with progressive, personalised exercise.

Your rehabilitation plan may focus on building strength, improving movement confidence, developing physical endurance and preparing your body for everyday activities.

The approach will depend on your assessment, how your symptoms respond and what you want to get back to doing.

Practical Takeaways: What Can You Do Today?

If you’re experiencing low back pain, a few practical changes may help you manage your symptoms while you work towards your usual activities.

• Keep moving gently: Avoid prolonged bed rest. Short, comfortable walks and other manageable activities can help you stay mobile without placing unnecessary demands on your back.
• Break up static positions: Set a reminder to stand, stretch or shift positions every 30 to 45 minutes if you sit for work.
• Focus on your breath: When pain flares up, we tend to hold our breath and tense up. Taking slow, comfortable breaths may help you relax and manage tension.
• Build activity gradually: If you’re returning to exercise, gardening or sport, start with an amount you can manage and increase it progressively.
• Prioritise sleep and recovery: Poor sleep and ongoing stress can influence pain sensitivity. Giving yourself enough recovery time is part of managing your overall physical load.

You don’t necessarily need to stop doing everything that causes discomfort. The goal is to find a manageable level of activity and adjust it as your symptoms change.

FAQs

What Is the Most Common Cause of Low Back Pain?

The most common type is non-specific low back pain, which accounts for approximately 90% of cases. This means pain cannot confidently be attributed to one particular injury, disease or structural change. Physical load, muscle sensitivity, activity levels, sleep and stress may all contribute.

Can Poor Posture Cause Low Back Pain?

There isn’t one universally bad posture that causes low back pain. However, staying in the same position for long periods can become uncomfortable. Regular movement breaks and changing positions throughout the day may be more useful than trying to maintain one perfect posture.

Why Does My Lower Back Hurt on One Side?

Pain on one side of your lower back can come from sensitive muscles, spinal joints or irritated nerves. Sometimes pain can also originate from structures outside the spine, such as the kidneys. The location alone isn’t enough to identify the cause, so an assessment may be helpful, particularly if you have other symptoms.

Why Is My Lower Back Stiff in the Morning?

Morning stiffness can occur after spending several hours in the same position overnight. It may ease once you begin moving. However, persistent or prolonged morning stiffness, particularly when accompanied by other symptoms, can sometimes indicate an inflammatory condition that needs medical assessment.

Can Low Back Pain Go Away on Its Own?

Yes. Many episodes of non-specific low back pain improve over several weeks, although the timeframe varies. Staying appropriately active and gradually returning to normal activities can form part of recovery. Seek professional advice if symptoms are worsening, persisting or interfering with your everyday life.

Is Low Back Pain the Same as Sciatica?

No. Low back pain refers to discomfort around the lower spine, while sciatica involves irritation of nerves that can cause pain to travel into the buttock or leg. Sciatica may also involve tingling, numbness or weakness. An assessment can help distinguish between the two.

Get Support for Low Back Pain

If back pain is interfering with your daily routine, caring for your family or enjoying your weekend, reach out to our team at Lilyfield Physiotherapy.

Our physiotherapists will take the time to understand your symptoms, assess your movement and discuss a treatment plan based on your needs.

Book an appointment at our Rozelle physio clinic and take the next step towards moving with confidence.