When you sleep on back,use this way:
“Roll a towel up and place it under the back of your neck to support your neck when you sleep at night. Adjust the height of the towel according to your cervical curvature and your comfort.”
But when you sleep on sides, you need a higher pillow.
Why? Let me explain: Not enough support will cause your neck injury and(or) shoulder blade injury.
Measure the length from the edge of your head to the edge of your shoulder. It should be much longer than the support of your cervical curvature.
Preparing a small pillow beside your head, when you turn on sides add the small pillow on to your regular pillow.