Doctors and Specialists are only human. Yes, they are qualified to diagnose an illness, but they too can make errors.
This is where it is important to always seek a second if not third advice. I know I have been misdiagnosed twice to my knowledge and I took it to be an error which can occur.
Knowing my own body and sometimes better than anyone else I can see how a misdiagnose can happen.
Don’t get upset if they get it wrong because it is up to you to gather more opinions and failing that the ball is certainly in your court.