For the last 3 years I have had pain in my upper left side. Some times t is in the back and shoulder aswell. It only seems to happen when I sleep on my left side and the pain normally wakes me up. I have been to the doctors a few times and have had some hearts tests and xrays done. They showed nothing. Sometimes I can go a week or so without having pain.

I've searched the internet and it seems a few people have this condition, but no one seems to know what it is.