I've had the privilege of being able to have access to some great hospitals. One in particular was called the 'best paediatric hospital ever' or some rubbish like that. I'd been there with disappointing results in the past, but we hoped I would be different this time. I was about ten years old, with no diagnosis and a flare that required hospitalisation for a week just two years prior. All signs pointed to juvenile arthritis.
Tendinitis. The world class doctor walked in, sat down, scanned my chart quickly and announced "she has tendinitis." He said ibuprofen would do the trick, wrote a note saying I could limit what I do in gym class and sent me away. World class treatment, eh? I know that in psoriatic arthritis, tendons may swell but I don't give him credit for noticing. Mostly since he didn't touch me and didn't have any X-rays or scans to reference.
Diagnosis is a difficult thing. It can take years to be heard (it took me about ten years). Don't give up in finding answers! You can't make something better until you know what's wrong. And don't let them dismiss you as normal; Normal isn't painful. You can't fix normal.