Comment by m0zg

If a fucked up left shoulder counts as "evidence", sure. :-)

Doctor prescribed an MRI and then suggested a surgery (with a minimum of 6 months of recovery). I declined. Turns out it was my sleeping position. I used to sleep pretty much exactly as shown, except towards the morning my arm would also go under the pillow, further straining the shoulder. Now when I sleep I extend the arm slightly downwards. This was sufficient to eliminate symptoms.

Obviously this will vary based on anatomy. Do a simple experiment. Lay down in this position and see if you have tension in the shoulder joint. If you're muscular (I am), you will very likely feel it. That tension, applied 8 hours each night, will most definitely cause issues.