How to get rid of my right thumb tendinitis?

Hey, I'm 17 years old and realized at the age of 16 that I had right thumb tendinitis for a long time now, yes I am young but I do have it. I use a brace to write etc but the pain still hurts with or without the brace. I went to physical and occupational therapy and it helped some what but it comes back and I already had 2 cortisone shots. TWO!... What should I do? Surgery was an option but...I don't want to relearn how to use my hand...its within my thumb...someone help me please...