Understanding Low Back Pain: What's Actually Going On?
If you've woken up unable to straighten your back, or you've had that dull ache sitting in your lower spine for weeks now, you're in very good company.
Low back pain is the single most common reason people come and see me, and it's the leading cause of disability worldwide, not because it's dangerous, but because it's so common and so disruptive to daily life.
I want to start with something that surprises a lot of people:
For the vast majority of low back pain, we can't point to one single damaged structure and say "that's what's causing it."
That's not me being vague, it's actually the nature of the condition. Researchers call this "non-specific low back pain," and it accounts for the overwhelming majority of cases that walk through a physio's door.
What is low back pain, really?
Non-specific low back pain means pain in the lower back where no single serious or clearly identifiable structural cause has been found — no fracture, no nerve compression, no underlying disease. That doesn't mean nothing is going on. It means the pain is usually coming from a combination of factors in the muscles, joints, discs, nerves and the way your nervous system is processing signals from that area — rather than from one clearly damaged part.
Only a small proportion of people with low back pain have a specific, well-understood cause like a fracture, cancer, or infection. For everyone else, the picture is more like a sensitive alarm system than a broken part.
What does it feel like?
Low back pain shows up differently for different people. You might notice:
A dull ache or stiffness across the lower back, often worse first thing in the morning or after sitting for a while
Sharp pain with certain movements, like bending forward or twisting
Pain that sometimes spreads into the buttock or upper thigh
Muscle spasm or a feeling of the back "locking up"
Pain that eases with gentle movement but flares with prolonged sitting or standing
For most people, this pain doesn't stay constant — it tends to ebb and flow depending on activity, stress, sleep and how much load you've put through your back that day.
Why does it happen?
This is where I want to gently push back on a few common beliefs. Low back pain isn't usually caused by "wear and tear" in the way people imagine — like your spine slowly falling apart. Research consistently shows that things like disc bulges and degenerative changes on scans are extremely common in people who have zero back pain at all, particularly as we get older. Finding something on an image doesn't automatically explain your pain.
What we do know contributes to low back pain includes a mix of physical and lifestyle factors, such as:
Physically demanding jobs, especially those involving heavy lifting, bending or awkward postures
A sudden increase in activity your back isn't used to
Reduced overall physical activity and deconditioning
Sleep difficulties
Stress, low mood, and how we're coping more broadly
Smoking
Carrying more weight than your body is currently used to managing
Previous episodes of back pain
Often it's not one single thing — it's a combination of physical load and how your nervous system and body are coping with everything else going on at the time.
Common misconceptions
A few beliefs I hear constantly in clinic that the evidence doesn't support:
"My spine is damaged" — in the vast majority of cases, there's no significant structural damage, even when pain is severe.
"I need a scan to find out what's wrong" — imaging is very rarely needed for straightforward low back pain and doesn't usually change the treatment plan.
"I should rest until it's completely gone" — prolonged rest tends to slow recovery down, not speed it up.
"Bending and lifting will damage my back" — your spine is a strong, adaptable structure that's built to bend, lift and load.
Is it serious?
For the large majority of people, low back pain — even when it's intense — is not a sign of serious damage and tends to settle over the following weeks. That said, there are certain symptoms that do warrant prompt medical assessment, because they can (rarely) point to something needing urgent attention:
New loss of bladder or bowel control, or numbness around the saddle area (between your legs)
Progressive weakness in both legs
Unexplained weight loss alongside back pain
Back pain following significant trauma, like a fall or car accident
Fever alongside new back pain
A history of cancer with new back pain
These "red flag" symptoms are rare, and research shows they're not perfectly reliable on their own — but if you notice any of them, it's important to get assessed promptly rather than wait it out.
When should you see a physiotherapist?
You don't need to wait until pain becomes unbearable. A physio assessment is useful any time low back pain is limiting what you want or need to do, whether that's been a few days or a few months. Earlier assessment often means earlier reassurance and a clearer plan, rather than searching symptoms online and assuming the worst.
What happens during a physiotherapy assessment?
A thorough low back assessment usually involves:
A detailed conversation about your symptoms, how they started, what makes them better or worse, and how they're affecting your daily life
Screening questions to rule out anything that needs urgent medical attention
An assessment of your movement, strength and how your back responds to different positions and loads
A discussion of what's likely contributing to your symptoms and what a sensible plan forward looks like
Is imaging usually required?
For most non-specific low back pain, no. Guidelines are consistent on this: imaging is generally reserved for situations where red flags are present, or where symptoms aren't improving as expected despite appropriate treatment. This isn't about withholding care — it's because scan findings are so common in pain-free people that they often don't provide useful information, and can sometimes lead to unnecessary worry.
What can you expect from here?
The good news is that most episodes of low back pain improve substantially within the first six weeks, though some people experience a longer or more recurrent pattern.
Understanding what's actually happening in your back — and what isn't — is often the first real step toward feeling more in control of it.
In the next article, we'll get into exactly what you can do about it: whether rest actually helps, what role exercise plays, and how to get back to doing the things you enjoy.
Continue reading: How to Treat and Manage Low Back Pain →
Suffering from Low back pain?
If you're dealing with ongoing or worrying low back pain, a physiotherapy assessment can help work out what's contributing to your symptoms and give you a clear, personalised plan forward.
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