If you wake up with a sore shoulder, avoid sleeping on your side, especially on the painful shoulder. It is also not advised to sleep on your stomach since it causes misalignment of the shoulders. The best sleeping posture is lying on your back. Put a thin pillow (an orthopedic pillow will work best for you) under your head. Take another pillow, place it on your stomach, and hug it. Your shoulders will now be in the correct and stable position. If you don’t like sleeping on your back, try lying on the side that is not painful. Draw your legs up slightly toward your chest, and place a pillow between your knees. Sleeping with your hand under your head is not advisable since it produces an unnatural position of the shoulder.