Dont use heat! It will make it feel worse. (dont worry, it's temporary, it's called Uhthoff's Phenomenon, which is a temporary worsening of symptoms in response to raised temperatures)

I get pain in my shoulders when I sleep at night too. I sleep on my left side, and rarely ever turn over or move once I fall asleep. (not sure why that is?)

I get a deep ache in my shoulder, I'm double jointed in both shoulders, and can pull my shoulders out of their sockets at will. I dont know if this has anything to do with the shoulder pain. A few years ago, I had such bad pain in my shoulder that I had to use a sling for a week or two because I couldnt even keep my shoulder in it's socket. I'd cry myself to sleep because it hurt so bad.

I also get a really deep ache pain in my left hip when I sleep on my side. A few months before I had any clue that I had MS, I had numbness in my right hip and thigh, so I was sleeping on my left side. The deep ache started then. At the time, it was so painful that if I tried to turn to my back, or other side, that I almost could not do it. I'd have to stuff my teddy bear into my mouth to keep from screaming as I slowly rolled onto my back.

It hasnt been that bad for a few months (thankgoodness!)

I'm starting to get a pain in my right knee when I'm sleeping (this could be from a knee injury I got when I fell down the stairs in January tho) But, I'll wake up, and the knee will be really stiff and painful, and bending it is pretty painful. It'll get better thru the day, but sometimes when I'm walking, I'll feel the kneecap feeling like it's caught onto something.

I dont think all my pains are MS related, but I'm sure one or two are not helped much by having MS and spasticity.