good question, i have rsd in my right hand/arm, and feels like its spreading up to my shoulder... i have had this for 9 months now, and for the first 3-4 months i could not sleep for anything...the most i would sleep is 4 hours a night, and taking ultram i was a walking zombie all day long...as soon as i switched medicines, i started getting a little more comfort..now i sleep on my back, but i am most comfortable on my stomach, although i cant fall asleep like that :/