Sleeping in the wrong position for your spine can often lead to chronic low back or neck pain, numbness in your arms and fingers, and shallow breathing (which in turn leads to fatigue). All of these can cause problems for you at night during as well as during the day. If you wake up feeling tired and sore even though it appears you’ve had enough sleep, then you may be sleeping in a position that is stressing out your spine. Making some minor adjustments to the position you sleep in can make a huge difference in how well you sleep and how you feel when you get up.
The ideal position for your spine is flat on your back without a pillow, because it allows your spine to rest with its natural curves in place. If you must have a pillow while lying on your back, make sure it is not a very thick one or it will push your head forward putting your neck in the exact opposite position of its natural curve, which can also cause headaches and neck pain.
If you can’t sleep flat on your back then the next best position is on your side, though this position can pose problems as well. People who sleep on their side (side-sleepers) tend to place their hand under their cheek where the nerves that run across the top of the shoulder and down the arm can get stressed after long periods of time – eventually leading to numbness in your fingers. And because the shoulder you sleep on gets hiked up towards your ear, the muscles of your neck and shoulder can get pinched or strained too. When sleeping on your side, be sure to use a pillow that fills the space between your ear and the outer edge of your shoulder. Doing yoga stretches first thing in the morning can also help loosen up muscles that have been strained during the night.
The worst position to sleep in is on your stomach – it forces you to keep your head turned to one side for extended periods of time putting a strain on your neck. For heavier people it can also put undue pressure on your lungs, impeding your ability to breathe freely.

