I'm glad others experience this. I thought I was doing it wrong. When DD was little, DH would sleep in the spare room to give us more room. If he was in with us it was because DD was having reflux/wind issues and was sleeping on his chest. It got better once DD was able to roll over and sit up from lying down.
I've found that having my arm up under my pillow and head is much more comfortable. I lie on my side and rest my head on the inside of my arm, rather than on top of my shoulder, and then adjust the pillow to better my neck and keep my head off of my shoulder (sorry not sure how to really describe it this early in the morning). It doesn't require rotating my shoulder as far and doesn't interfere with blood flow. It also allows a little more freedom of movement. I also have upper back and neck issues but they are no worse than usual while sleeping like this.

