I just know enough to be dangerous...
(for example, I'm quite convinced that I know exactly what is going on with you and exactly why and exactly how to correct it... dangerous! Hubris! Run away!)
Bike shop fits are nice, but when you are having a medical problem it really helps to have a medical person check you over on the bike. Most PT's can see what your body is doing if you ride on a stand in their office until the pain starts, and they can see what needs help even if they don't know much about bikes.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson