Hi Zoey,
Some people just tend develop a lot of extra scar tissue, you might be one of those.
I wish they would have suggested that you not continue with the ball playing...

I wish my drs would have stressed how my multiple RSIs could become a chronic issue like TOS , but none mentioned anything like that.
1 dr did say I should not continue doing repetitive work , but the WC took him off my case at that point..

But I might have listened if many of them had said the same thing.

But it is hard to give up things we love doing..

I don't know if the sx you are having now are scar tissue related or not.
have you been doing any PT or self care gentle stretching?

Look up Sharon Butler's website - www.selfcare4rsi.com

for her thoughts on how do very gently stretch damaged tissues - explore the whole site & articles.