Sleeping on your side can actually ruin your spine because of gravity forced upon it, mostly your neck IF it’s not straight. If your neck does not align with your spine, or straighten with your vertebrae, while sleeping on a pillow, you are going to have a ruined neck for the night. To prevent this, buy a cube pillow. It’s a pillow that’s a cube.
People who are professionals with vertebrae studies, fact check me so I can make corrections.