Lower back pain is one of the most common health complaints in New Zealand, and the majority of people will experience it at some point in their lives – often more than once. It can be deeply disruptive, affecting the ability to work, sleep and carry out everyday tasks. A frequent question physiotherapists hear is: what is actually causing this? The honest answer is more nuanced than most people expect, and understanding it can make a real difference to how you approach your recovery.

Why a specific cause is often not found

Research consistently shows that a specific anatomical cause for lower back pain can only be identified in fewer than 20% of cases. In the remaining 80% or more, no single structure can be pinpointed as the source — even with imaging. This is not a failure of assessment; it reflects the genuine complexity of the spine and the way pain works.

It is also important to know that the intensity of your pain does not necessarily reflect how serious the underlying issue is. Lower back pain can feel sharp, burning, aching or stabbing — and two people with identical levels of discomfort may have quite different experiences of what is driving it. Pain intensity and tissue damage do not always correspond.

Mechanical lower back pain

The large majority of lower back pain is categorised as mechanical lower back pain. This term describes pain that cannot be attributed to a specific identifiable structure, but that changes in response to movement, position or activity. It encompasses the broad range of strains, sprains and musculoskeletal pains that affect the lower back in daily life.

Mechanical lower back pain does not typically show up on an X-ray or MRI scan, which is one reason imaging is not routinely recommended in the early stages. When the spine moves, all of its structures — discs, joints, ligaments and muscles — move together, making it genuinely difficult to isolate a single source of pain through testing alone. Your physiotherapist will use clinical assessment to identify the factors that are most relevant to your situation.

When a scan may be needed

In most cases, an X-ray or scan is unlikely to provide information that changes how your lower back pain is managed. Given that X-rays and CT scans also deliver a dose of radiation, it is sensible to avoid them when they are not clinically necessary.

There are specific circumstances where imaging is appropriate, and your physiotherapist will be able to advise if any apply to you:

• If you are experiencing problems with bladder or bowel function
• If your pain followed a fall or direct impact to the back and a fracture is suspected
• If leg pain has persisted for more than six weeks without improvement

Where a scan or referral to another specialist is needed, your physiotherapist can guide you through the appropriate pathway.

How recovery works

The good news is that identifying a specific cause is not a prerequisite for effective treatment. Physiotherapy plays a crucial role in managing lower back pain, even when the source remains non-specific. A thorough assessment allows your physiotherapist to develop a personalised rehabilitation plan that addresses all the contributing factors — not just the physical ones.

A comprehensive plan typically considers how you move, the demands of your work, your sleep quality, stress levels and how your environment may be influencing your symptoms. When these factors are addressed together, most lower back pain resolves within six to 12 weeks.

For practical guidance on gentle movement during recovery, our article on stretches for lower back pain recommended by physiotherapists offers a helpful starting point.

Finding the right support

Lower back pain does not need to have a clear-cut diagnosis in order to improve — what matters most is getting the right assessment and a tailored plan that fits your life. Whether you are dealing with a recent episode or longer-standing discomfort, the physiotherapy team at Active+ can help you understand what is driving your symptoms and support your recovery from there. Find your nearest Active+ physiotherapy clinic to get started.