You bend down to grab the laundry basket and something pinches. Or you sit through a long meeting and stand up stiff. Lower back pain shows up in dozens of ways, which is part of what makes the causes so confusing.
There isn’t one single answer. There are several common lower back pain causes, each with its own pattern of symptoms, triggers and recovery time. Most people guess, push through, and hope it settles. Some pain does. Some doesn’t. This guide walks through what’s likely going on, how to tell, and the signs that mean it’s worth getting properly checked.
What Causes Lower Back Pain?
Lower back pain is one of the most common health complaints in Australia. According to the Australian Institute of Health and Welfare, around 1 in 6 Australians have back problems, which works out to roughly 4 million people. Part of the reason it’s so widespread comes down to anatomy. The lower back, or lumbar spine, carries the weight of your upper body and absorbs force from almost every movement you make. It’s built from five vertebrae, the discs that cushion them, plus a network of muscles, ligaments and small joints called facet joints. That’s a lot of moving parts, and any one of them can become a source of pain.
Most cases are mechanical. The structures aren’t damaged in any catastrophic way, they’re just irritated, overloaded or moving in a pattern your body doesn’t like. That’s why two people with what looks like the same symptom can end up with very different findings on assessment.
1. Muscle and Ligament Strain
This is the most common cause of lower back pain by a wide margin. A strain happens when a muscle or ligament gets stretched or torn beyond what it can handle. The classic triggers are lifting something heavier or more awkwardly than you’re used to, twisting suddenly, or doing too much volume too soon at the gym.
A strain usually feels like a deep ache that’s worse with movement and eases when you’re still. You might notice tightness, mild swelling, or a tender spot when you press on it. Most strains settle within a few days to a couple of weeks with relative rest, gentle movement and time.
2. Disc Issues
Between each vertebra sits a disc that works as both a shock absorber and a pivot point. Discs can bulge, herniate or wear down. When a disc presses on a nearby nerve, the pain can travel into the buttock or down the leg, sometimes with pins and needles or weakness. This is what people usually mean when they say “sciatica,” though sciatica is a symptom rather than a diagnosis.
Disc-related pain tends to feel sharper, can be position-dependent (often worse when sitting, better when standing or walking), and may take longer to settle than a simple muscle strain. Not every disc issue needs imaging or specialist treatment, but persistent leg symptoms are a good reason to get assessed.
3. Joint and Posture-Related Pain
The small facet joints at the back of the spine handle a lot of the bending and rotating you do. When you spend hours in one position, especially seated, they can stiffen and become irritated. The same goes for the sacroiliac joint, which sits where the spine meets the pelvis.
This is the everyday “office back” people describe. It’s often dull, central or one-sided, worse after long periods of sitting or standing in one spot, and noticeably better once you move around. Posture isn’t the villain it’s sometimes painted as. Staying in the same position for too long does load the same structures over and over, and that’s where the trouble starts.
4. Gym and Training Injuries
For people who lift, run or play sports, lower back pain often traces back to a specific movement or a gradual loading error. The big culprits are deadlifts and squats with a rounded lower back, repetitive flexion under load, or jumping a training program forward without enough recovery. Endurance runners get a slightly different version, where the deep core muscles fatigue before the legs do, and the back picks up the slack.
If you train regularly, the question isn’t whether to stop entirely but which movements to back off, which to modify, and what’s missing from your program. A targeted physiotherapy assessment can usually pinpoint that within a session or two.
5. Recurring or Chronic Lower Back Pain
Pain that lingers past three months, or keeps returning every few weeks, is usually a different conversation. By then, the original tissue irritation has often settled, and what’s left is a combination of movement habits, deconditioned muscles, and sometimes a nervous system that’s become more sensitive to load than it needs to be.
Recurring back pain doesn’t mean something is structurally wrong. More often, it means the body needs help building tolerance back up. Approaches like graded loading, strength work and clinical Pilates tend to do well here because they rebuild capacity in the structures that were avoiding load.
6. Less Common but Important Causes
A small percentage of lower back pain has a specific medical cause that needs proper investigation. These include fractures (especially after a fall or in older adults with reduced bone density), infections, inflammatory conditions like ankylosing spondylitis, and rarely, tumours. They make up a small slice of cases, but they exist, which is why a few warning signs always warrant a medical review.
When to Get Lower Back Pain Checked
Most lower back pain settles on its own or with some basic movement, ice or heat, and pacing. There are situations where it’s worth booking an assessment sooner rather than later. The list below mirrors the red flags that Healthdirect and most Australian clinical guidelines highlight for back pain:
- Pain that hasn’t started improving after one to two weeks
- Pain that travels into the leg, especially below the knee
- Numbness, pins and needles, or weakness in the leg or foot
- Pain that wakes you at night or stays the same regardless of position
- Loss of bladder or bowel control (rare, but a reason to seek immediate medical care)
- Pain after a significant fall or accident
- Unexplained weight loss, fever, or a history of cancer alongside back pain
If any of those apply, getting a proper assessment is the right move. Even when none of them applies, if the pain is interfering with sleep, work or training for more than a couple of weeks, an assessment will usually save time.
What a Lower Back Pain Assessment Actually Looks At
A first session with a physio typically involves a conversation about what triggered the pain, how it’s behaving day to day, and what you’ve already tried. After that, it’s a movement assessment looking at how your back, hips and core work together. Imaging, like an X-ray or MRI, is sometimes useful, but for most cases of lower back pain, it doesn’t change what gets done first, so it’s not always the starting point.
The treatment plan from there depends on what the assessment shows. For some people, it’s a few sessions of hands-on work and a short home program. For others, it’s a longer-term plan focused on strength and load management. The goal is to get you back to the things you stopped doing and keep you there.
When Self-Care Is Enough
If the pain is mild, getting better day by day, and not behaving in any of the ways listed above, gentle movement, walking, and avoiding long stretches of sitting or bed rest are usually all that’s needed. Avoiding movement entirely tends to make things worse, not better.
Lower Back Pain: Your Questions Answered
| Question | Answer |
|---|---|
| What are the most common causes of lower back pain? | Most lower back pain comes from muscle or ligament strain, disc irritation, joint and posture-related load, or training-related injuries. A small number of cases involve specific medical conditions that need investigation. The most common causes are mechanical and tend to settle with movement, time and graded loading. |
| How do you know if lower back pain is serious? | Warning signs include pain travelling below the knee, numbness or weakness in the leg, pain that wakes you at night, loss of bladder or bowel control, or back pain following a significant fall. Pain that hasn’t started improving after one to two weeks is also worth getting assessed. |
| How long does lower back pain usually last? | Most simple lower back strains settle within a few days to a couple of weeks with movement and pacing. Disc-related pain can take longer. Pain that lingers beyond three months, or keeps returning, is considered chronic and usually benefits from a structured plan rather than waiting it out. |
| Can lower back pain go away on its own? | Yes, most acute lower back pain improves without specific treatment, especially when you stay gently active rather than resting in bed. If the pain is mild, easing day by day, and not behaving in concerning ways, basic self-care is often enough. Persistent or recurring pain usually needs a more considered approach. |
| Should I get an MRI for lower back pain? | For most lower back pain, imaging like an MRI doesn’t change the initial treatment plan, so it’s not the first step. Imaging becomes useful when symptoms point to a specific structural cause, when there are nerve symptoms in the leg, or when pain isn’t responding to treatment after several weeks. |
| When should I see a physio for lower back pain? | Book a physio assessment if your lower back pain isn’t improving after one to two weeks, keeps returning, travels into the leg, or interferes with sleep, work or training. A physio can identify what’s driving the pain and build a plan that goes beyond waiting for it to settle. |
Final Thoughts
Lower back pain causes range from a one-off muscle strain that settles in a week to longer-running patterns that need a more considered plan. Knowing roughly which category your pain fits into makes it easier to decide whether to ride it out, change something in your routine, or get a professional involved. For a deeper look at the treatment and what recovery typically involves, we can walk you through the full picture of conquering lower back pain.
Book an appointment with one of our experienced physiotherapists today for a comprehensive assessment and customised treatment plan.
