my left should aches all the time. it pops and makes noises when moving it vertically, it aches worse when I sleep on it of course. I cannot sleep on my arm and pillow but must place the pillow directly under my head to even get to sleep. I use salonpas gel 1 - 2x daily which helps to relieve the pain. The scary part is that I get tingling in my arm to the finger tips and experience temporary numbness in my left thumb on occasions such as today. I went through a whole series of physical therapy last year focused on my neck which I also have less issues with. previous to that I went to the doctor who had xrays taken and suggested that it was a for of arthritis. sorry but I am not so trusting that this is only that.