Lower Back Pain When Lying Flat On Your Back

There are two reasons why you could get back pain when lying flat on your back. On the one hand you could get some dull achy back pain that comes on slowly. The other type of pain you might experience is a sharp or jarring pain point at the lower part of your spine. Today we’ll be explaining the cause of these two different sorts of back pain that happen when you lie down, and what you should be doing to fix them.

Back pain type one: dull aching lower back when lying flat

For some when they lie flat they experience a gradual building of pressure or aching in the lower back that creeps in making lying down steadily more uncomfortable. In this case it is caused by the lower back steadily flattening out and stretching the back of the spines ligaments and discs. If there is an existing lower back issue, for example a disc bulge at the L4-L5 segment, this back pain when you’re lying down could be the first signs you might experience. When you take a step back and think about it you might also notice some stiffness or aching when you’re sat down during the day. 

Your lower back should have a natural backward bending arch and in this instance, the arch is being easily lost, stretching the discs and ligaments, aggravating the underlying injury. Additionally some people feel a more gradual build up over many minutes, perhaps when going to bed. In this instance, it is commonly the build up of inflammation around the spine that creates this pressure feeling. 

Back pain type two: sharp pain when laying down flat

Some people notice that when they lie down they can get a sharp or jarring pain. This can be a lot more focused than the previous type of pain, it can even go down the leg as in the case of sciatica, if the nerve gets caught in the right place. These cases of back pain affect the same sort of area of the lower back, with some slight differences. Usually it is a case of the L5-S1 segment being a primary factor, with the opposite movement to that previously mentioned.

When you lie down on your back, the tightness that might be present in your hips from sitting all day pulls on the front of your pelvis and spine and creates an “anterior pelvic pull” which tries to pull the pelvis forwards. You might feel this as you straighten your legs, Your lower back is pulled into more of an arch and the jarring feeling comes on. In this case, slight movements  to one side or the other can often cause the facet joints to “jar” or “catch”. 

This sort of pain is usually some combination of injury and instability to the L5-S1 segment, tightness in the hips, and stiffness in the other levels of the low back. As a result the L5-S1 segment moves more than it should and is being strained when you try to lie flat. This is made more noticeable if there is any inflammation in the low back, as the movement of the back arching further quickly makes the little holes the nerves come out of smaller, increasing the likelihood of them being “trapped” and sharp pain being felt, either in the back or down the leg.

What can you do about back pain when laying flat

There are some short term suggestions that you can take to help reduce the likelihood of being in pain when you lie down. These little hacks can help you, but they are short term relief. We’ll cover some longer term options later on too so you can be rid of this back pain once and for all!

Support the natural curve to reduce your low back pain

The best option for moment to moment relief is to support your natural curve. We always recommend the “towel exercise”. This is the best way everyone can do this at home. Using a small rolled towel to support your lower back’s natural arch. We explained why this is the best stretch for lower back pain in a dedicated episode of the podcast if you want to understand it better.

Howe to do the towel stretch for low back pain when laying down

• Take a bath towel, fold it in half length ways then roll it up
• Lie on your back with knees bent, feet on the floor
• Lift your bum up and slide the towel in to support the low back curve
• The towel should be opposite your belly button as a check
• Lower your body over the towel and feel it support your arch
• Relax into this position for 20 seconds to 5 minutes at a time
• When done, roll your whole body to the side to dismount
• Do NOT twist your low back or lift your back off the towel.
• You can repeat this two or three times a day.

This towel stretch for lower back pain when lying down is a great one because it addresses both causes of the lower back pain when lying down. Firstly, it stops the back flattening out when you lie down, which is the reason for the first dull aching pain when you lie down on your back. The second is that it makes sure that all the joints in your lower back share in the backward bending movement, and your hips remain bent, this reduces the pressure forcing the L5-S1 to try to hinge and give you that “sharp” or “jarring” pain in the lower back, or down the leg. 

Other strategies to reduce pain when sleeping on your back

It can be tempting to try to sleep with pillows under the legs when you have lower back pain, the problem with this is that it only serves to flatten the lower back more and help the issue of lower back dysfunction continue. Instead while in a lot of pain when lying on your back, try sleeping on your side instead. Using pillows to support and bolster your body for maximum comfort without compromising your lower back position. 

We discussed sleeping with lower back pain on a dedicated video so you can read and watch more there, but while you’re here, check out the steps and pillow options below:

Pillow placements for lower back pain when sleeping:

• Sleeping on your side is going to be the best position for your lower back
• Using one pillow between the knees helps take tension off your glutes 
• Having your thighs at a 45 degree angle reduces the pull on the lower back
• Having a small towel supporting your waist holds your spine straight
• A pillow behind your back will support your torso from rolling
• Hugging a pillow between your arms will square your shoulders
• Using one pillow to support your head and keep your neck straight

It might sound like a lot but even some of these pillow placements can make it so your spine is held supported in the best sleeping position with minimal strain pulling your back one way or another. Give some or all of them a go tonight!

Long term strategy to reduce back pain when you lay down

Ultimately a healthy lower back is not going to have pain when you lie down. The fact that you’re experiencing pain when you lie down flat is an indication that there is some minor injury down there in your low lumbar spine. The best way to deal with this is to be proactive, using the towel like mentioned above as well as keeping your hips mobile through proper hip stretching is a good start but you will find no long term relief unless you incorporate the strengthening process into your daily regimen.
This means building the strength of your core and lower back to protect your spine from the stresses of day to day life. If you’re not sure where to begin, that’s no problem, you can check out our full 80 minute “Fix Lower Back Pain Masterclass” where we cover everything you need to start to rebuild your lower back health for the long term. If you want a little more help you can always reach out to us to learn more about the Membership to the Back In Shape Program where we help people just like you, from all over the world, fix their back pain from home.