Why does my lower back hurt when i lay down on my stomach

When individuals sleep on their stomach, the lumbar spine can go into excessive hyperextension. This jams the posterior elements of the spine together which can lead to pain.

Intervertebral discs wear down and lose their ability to cushion the vertebrae. Discs can also become herniated or ruptured, causing a bulging disc that may compress spinal nerves and cause pain. The nerves may get more compressed when sitting, making back pain worse when lying down or sitting.

The best sleeping position for lower back pain is on your side with a partial bend in the knees⁷. Keeping the knees bent helps balance the body and reduces pressure on the lumbar spine. Many people find it helpful to put a small pillow between their knees to make this position more comfortable.