I just posted one undiagnosed topic and I'm going to post on another.
About a year ago I had extremely bad pain on the inside of my elbow. This lasted for several weeks but the doctor couldn't find a cause of it. It hurt so badly that I couldn't sleep at night and was taking pain killers.
One day at work, something suddenly dawned on me. I worked in a customer sales office where staff must dial all day long. The office chairs had arms on them. What if I sat on a chair without arms?
Sure enough, it worked! All of that time, my elbow had been getting inflamed only because of the movement of the forearm against the chair arm each time I dialed. If you do a lot of telephone dialing, find a chair without arms! You may think your chair is NOT affecting it because you can't feel the irritation each time, but if your arm is inflamed at night it's certainly worth a try!