Brian, I think you are on to something there. I was having issues with shoulder pain, and thought it might be problems with my rotator cuff? I am a side sleeper, and noticed that sleeping on my side made it much worse (no surprise really). I tried unsuccessfully to sleep on my back to cure this- but I just can not sleep that way. I tried googling side sleeping and shoulder problems and happened upon a suggestion that it wasn't sleeping on your side that hurt your shoulder- but sleeping with your hand up under your head. The suggestion was to keep the bottom arms down closer to your side. I tried it, and it did get rid of my shoulder pain (while still being able to sleep on my side! ). But, after reading your post I noticed that I wasn't having problems with my hands (possible carpal tunnels) anymore too. So- I believe your suggestion is good for the hands and the shoulders!
CARPAL TUNNEL SYNDROME CURED
Twelve years ago I was sure I had Carpal Tunnel Syndrome but never had it confirmed by a doctor, just to avoid any possibility of being told that surgery was the only option. My right hand wrist got so sore that on a bad day, at my desk job, I couldn't push a pen for more than a minute before having to rest it. I made makeshift splints for my wrist using rulers and rubber bands just for some relief when using the keyboard. Never did have a day off work but this went on for a few weeks. Then I tried something so simple that costs absolutely nothing and takes no effort at all except an awareness. I was cured in just a few days and have had no recurrence of the syndrome ever since. That's not a knife, that's a testimony.
In one sentence, when asleep, keep your hand away from underneath your head. I believe many cases diagnosed as Carpal Tunnel Syndrome might be cured simply by adjusting the sleeping position to keep the hand away from under one's head.
Having always preferred to sleep on my tummy with my head to the right, my right hand would automatically position under the pillow under my head, with the wrist directly below my jaw. A human head already weighs upwards to 5kg but with the added force of the spine pushing the head into the pillow to level the body, the total weight borne by the wrist in such a position has to be a lot more. Add a long time such as a night's sleep and voila, a sore wrist develops with all of the compression symptoms that could easily be diagnosed as CTS by experts. I simply changed to sleeping on either one of my sides with one hand still under the pillow, but only a little bit along the edges where there is no weight on it at all.
If you are just one of apparently 10% of the population who develop CTS who try this sleeping position adjustment cure and you have success and avoid surgery - I would be delighted to know. Good luck.