One way to reduce shoulder pain caused by sleeping on your side is to lay in a "hug" position, where you extend your bottom arm straight out, reports Women's Health. Next, use both arms to gently hug a pillow to your chest.
Curling your arm up to rest your head on it is a common cause of shoulder pain due to side-sleeping, according to Women's Health. This stresses the brachial plexus, a complex of nerves in your neck and shoulder, and leads to pain. If one of your shoulders is already sore, let that be the top shoulder until it heals. If both of your shoulders are sore, sleep on your back for a time to give them both a rest.
It is also recommended to switch sides regularly, suggests Everyday Health. Always sleeping on the same side can cause long-term imbalances as the bottom side compresses and the top side stretches. This can lead to chronic soreness over time.
If you find sleeping on your side too painful, experiment with rolling your shoulder slightly forward or backward, suggests Medical Advanced Pain Specialists. Use pillows to help support your position and keep yourself in place as you sleep. A rolled towel or small pillow under your neck can help alleviate neck pain, which can be related to shoulder pain.