Why Does My Back Hurt When I Lie Down?
Back pain when lying down often happens because your spine changes shape when you go from standing to lying flat. Lying down takes away the load of gravity. But it also changes how your joints, muscles and discs sit. Conditions like facet joint wear, tight hip flexors or a lower back that curves too much can feel worse in bed. This is because certain positions squeeze structures that are already irritated.
Key points
- Lying flat changes the load on your spine. It can increase pressure on worn joints or tight muscles.
- Back pain in bed is not always about your mattress. It may point to a structural or alignment problem.
- Night pain that does not let up, wakes you and does not ease in any position is a warning sign. Get a medical check urgently.
- Standard scans are done lying down. They can miss alignment problems that only show when you are upright and bearing weight.
- A standing whole-body scan shows your spine under real, everyday load. This helps clinicians see what flat scans hide.
You spend all day on your feet without trouble. Yet the moment you get into bed, your lower back starts to ache. Or you wake at 3 a.m. with stiffness that takes half an hour to ease. If that sounds familiar, you are not alone, and you are right to want an explanation.
What causes back pain when lying down?
Several common conditions cause or worsen back pain in bed. When you lie flat, your spine takes on a different curve than when you stand. That change can squeeze joints, stretch tight muscles or shift pressure onto structures that are already inflamed.
Lying on your back can push the small joints at the back of each vertebra together. If those joints are worn or inflamed, this causes a dull ache in the middle of the back. Learn more about facet joint arthropathy.
Sitting all day shortens the hip flexor muscles at the front of your pelvis. When you lie flat, these tight muscles pull your lower back into a strong arch. This increases strain.
Discs soak up fluid overnight and swell slightly. If a disc is already bulging or damaged, this extra volume can press on nearby nerves. This makes morning stiffness worse.
When the spinal canal narrows, some lying positions can reduce the space left for nerves. This may cause aching, tingling or heaviness in the legs at night. Read more about spinal stenosis.
Your mattress and pillow play a part too, but they are rarely the whole story. If you have tried a new mattress and still wake in pain, it is worth looking at the structural side.
How do I know if my back pain in bed is structural?
Structural or mechanical back pain tends to follow patterns you can recognise. If one or more of the signs below match what you feel, your spine's alignment or joint health may be involved.
Pain that flares when you lie on your back but eases on your side, or the other way round, often points to the facet joints or a disc.
If you feel locked up when you wake but loosen up within 20 to 30 minutes, inflammatory or wear-and-tear changes may be involved.
Pain that creeps in after an hour or two in bed suggests that staying loaded in one position for a long time is irritating a specific structure.
If getting up and moving eases the pain quickly, the problem may be linked to how your spine sits when it is not loaded, rather than when you are upright.
When is back pain that is worse at night a warning sign?
Most back pain in bed is mechanical and not dangerous. But certain patterns need urgent medical attention. If any of the following apply to you, contact your doctor or go to the nearest emergency department rather than booking a scan.
- Pain that does not let up and does not change with any position, including pain that wakes you from deep sleep and never settles.
- Numbness or weakness in one or both legs, especially if it is getting worse.
- Loss of bladder or bowel control, or numbness around your groin or saddle area.
- Unexplained weight loss, fever, or a history of cancer together with new night pain.
These can be signs of conditions that need a medical check the same day. Do not wait.
Why do lying-down scans sometimes miss the cause?
Standard X-rays, CT scans and MRI are usually done with you lying flat. That position relaxes your muscles and takes the load of gravity off your spine. The result is a picture of your spine at rest, not under the forces it deals with all day.
This matters because alignment problems, joint compression and compensatory curves depend on gravity. They appear when you are upright and may disappear the moment you lie down on the scanner table. That is why a scan can come back "normal" even though you are clearly in pain.
An EOS scan is taken while you stand. It captures your whole skeleton from head to feet in a single image, using about 90% less radiation than a standard X-ray, around ten times less. Because you are bearing weight, your clinician sees your spine exactly as it behaves in daily life. Read more about weight-bearing versus lying-down imaging and how ScanAlign standing EOS imaging works.
A note on MRI. EOS shows bones, joints and alignment in excellent detail. For soft-tissue problems such as discs, nerves or ligaments, MRI is usually the better tool. The two scans answer different questions. Your clinician can advise which one you need, or whether you may benefit from both.
What can help with back pain when lying down?
The right approach depends entirely on the cause. That is why it matters to get an accurate picture of your spine's structure and alignment before you commit to any treatment plan. Some general steps people find helpful include:
- Changing your sleeping position. A pillow under your knees when you lie on your back, or between your knees when you lie on your side, can reduce strain on the lower spine.
- Gentle movement before bed. A short walk or light stretching may help your muscles relax. It may also reduce the sudden change from being active to lying still.
- Dealing with tight hip flexors. If you sit for long periods, your hip flexors may pull your pelvis forward when you lie flat. A physiotherapist can assess this.
- Understanding your alignment. If your pain keeps coming back after trying different mattresses, pillows and exercises, the next step is often a scan that shows how your whole skeleton lines up under load.
Before you start a treatment, or change the one you are on, it is worth getting a detailed diagnosis. Knowing whether the cause sits in your pelvis, your legs or your spine changes what will actually help.
If you have had back pain in bed for more than a few weeks and standard scans have not given you a clear answer, a standing whole-body scan may show what has been missed.
Book a free video consultationFrequently asked questions
Lying flat increases the natural curve of your lower back. If your facet joints are worn or your hip flexor muscles are tight, this position squeezes or stretches structures that are comfortable when you are upright. A pillow under your knees can reduce this curve and ease the load.
Most night-time back pain is mechanical and not dangerous. But pain that is constant, wakes you from sleep, does not change with position, or comes with numbness, weakness, or bladder or bowel changes needs an urgent medical check. Contact your doctor or go to the nearest emergency department.
A very old or unsupportive mattress can play a part, but it is rarely the only cause of persistent back pain. If you have tried a new mattress and the pain continues, the problem is more likely structural. A scan can help find out what is going on inside your spine.
Overnight, your spinal discs soak up fluid and swell slightly. This extra disc volume can press on nearby structures. It causes stiffness until you move around and the discs settle back to their daytime size. Inflammatory conditions can also cause long-lasting morning stiffness.
Many people find lying on their side with a pillow between the knees most comfortable. If you prefer lying on your back, a pillow under your knees can reduce the arch in your lower spine. The best position depends on the specific cause of your pain.
MRI is done lying down, which relaxes your muscles and takes gravity out of the picture. Alignment problems, joint compression and compensatory curves that appear when you are upright may simply not show on a flat scan. A standing EOS scan captures your skeleton under real, everyday load.
An EOS scan is taken while you stand and captures your full body in one image. It uses about 90% less radiation than a standard X-ray, around ten times less. This gives your clinician a complete picture of how your spine, pelvis, hips and legs line up under gravity.
No. ScanAlign is a private, self-pay clinic and you can refer yourself. You start with a free video consultation to make sure the scan is right for your situation.
Yes. The EOS system uses about 90% less radiation than a standard X-ray, around ten times less. It is one of the lowest-dose methods of imaging the skeleton available.
The price for patients travelling from abroad is confirmed during the free video consultation, which you can request from the book a spine assessment page. ScanAlign is a private, self-pay service.
Still waking up in pain?
A free video consultation lets you talk through your symptoms before you plan a trip to London. You can find out whether a standing whole-body scan could give you the answers that lying-down scans have missed.
Book a free video consultationSources
- NHS. Back pain: causes and when to get help. nhs.uk. Available at: nhs.uk/conditions/back-pain
- Dubousset J, Charpak G, Dorion I, et al. A new 2D and 3D imaging approach to musculoskeletal physiology and pathology with low-dose radiation in standing position: the EOS system. Bulletin de l'Académie Nationale de Médecine. 2005;189(2):287-297.
- National Institute for Health and Care Excellence (NICE). Low back pain and sciatica in over 16s: assessment and management (NG59). 2016, updated 2020.
Written by Abbas Dhami (Specialist Diagnostic Radiographer)
This page is general information and not a diagnosis.
ScanAlign is the trading name of CoreMed Solutions Ltd and operates under The Harley Street Hospital's CQC licence.