There are two good positions to sleep in bed if you have back or neck pain or a spinal injury: on your back with a pillow beneath bent knees or on your side with a pillow between the knees and elbows. Avoid sleeping on your stomach; this can torque the low back and neck, creating stiffness or pain.
Avoid Sleeping on the Belly
Sleeping on the belly is not really appropriate for anyone. Babies shouldn't be put to sleep on their bellies, because this is associated with sudden infant death syndrome.
If you sleep on your stomach, your head will turn to the side and this twists the neck and C-7 vertebra (the seventh vertebra of the cervical spine). Few doctors will recommend sleeping on the stomach for this reason.
Sleeping on the Back
Sleeping flat on the back prevents the neck and low back from arching and placing the head and pelvis in a position that would create compression in the joints and bones.
Placing a pillow under bent knees keeps the low back in a neutral position.
Using a compression foam pillow with a hollow trough will support the cervical bones of the neck.
When you sleep on your back, lungs and other organs are evenly spaced and can rest without being crowded or twisted.
Sleeping on the Side
Sleeping on the side will keep the spine and neck in alignment. Place a long body pillow between the knees and elbows to help you keep the S-curves in the body while not compressing your neck and low back. The S-curves are in the C-7 (neck), T-12 (thoracic spine) and L-5/S-1 (lumbar and sacrum) vertebrae.