The "Bow-Tie" Pillow Method
People who move their head constantly and wake up with stiff necks can give this a try.
Take your normal pillow and take string, rubber band, or something similar, and tie the pillow down like a bowtie. Now sleep with the back or side of the neck in the middle of the bowtie and watch as your neck will not be able to move around, thus leaving it in a sustained position while you sleep. You won't be able to move the head side to side because the sides of the pillow will be elevated. Give it a try if you are suffering from neck pain.