Hi I have had severe shoulder arm and wrist pain and aching behind the knees for a period of three weeks now. I went to my doctor and she prescribed me with Naproxen 500mg they took the pain away slightly but It is still affecting me badly and I'm unable to go to work. Any ideas as to the cause as this came on so suddenly. I work as a fencer which is a very physical job but have not suffered like this before.