Suggest Treatment For Severe Pain In Back,neck And Shoulder

I am 36 and have been having severe neck and back paind (to just below shoulder area. My left shoulder elbow and hands seem to be effected as well as my left knee that "give out" while walking. X-rays and MRI showed arthritis however the doctor does not believe that would case the pain I'm experiencing. this has been going on for over a year and I'm always given the "pill of the week" which is causing pains in my stomach. I am frustrated that i can't seem to get any relief from the pain. Please offer advice. Thanks