Yes, I've seen this shoulder pain thing before; and by what you describe it's pretty rare but unfortunately its severity happens, and it happens very painfully to the extent that it keeps you awake at night repositioning your pillow with your arm bent underneath...Right? (That's exactly right isn't it)
You probably have cancer of the prostate or testicles from improper seat positioning, whereby if you pull down your zipper with your right hand on bike trails to urinate, repeatedly doing so over and over again because you drink a lot of water, the symptomatic pain begins to insidiously migrate from the right shoulder and into your testicles like they did with Lance Armstrong until it finally became unbearable -- and like Lance Armstrong who couldn't keep it up even when his wife used to do dirty dances for him standing over his head, Lance began to discover his wife fooling around with other bicyclers and they ended up getting a divorce.
If I were you, I'd copy-paste this missive onto a MS-Word file, print it, and take it to your doctor right away so he/she can consult a good urologist and save your life.