I actually had my shoulder replaced a few years ago. It began while I was competing in Strongman, lifting heavy stones and pressing them overhead. After two years of rehab, I'm able to throw.
Here's why I say that: I've become quite the student of anatomy and physiology since then. My shoulder wasn't "injured." I found out that I had a disease called Avascular Necrosis in every joint, and it stemmed from Juvenile Rheumatoid Arthritis which I thought had gone into remission forever. It reared it's head at the very end of my Army career thank goodness. Anyway, I've always ached and hurt more than other folks, living off of Tylenol and Ibuprofen and thinking that was the way it was. I pitched in high school and always hurt.
OK, OK...I'm getting there. Anyway, repetitive throwing will, over time, wear your joints down. "Over time" may mean ten years, or it could be seventy years. Do you know what determines that? Technique and correct throwing form.
If you are still hurting, continue to rehab under the care of a Sport's PT. They will better understand your wants and needs. They will teach you how to tweak your throwing form to do the least amount of wear and tear on the joint, especially the injury that you have. Chances are, over time, you've developed a comfortable yet incorrect throwing form that strains your ligaments, tendons, and muscle. Correct it, and your shoulder will last. I am proof that it can be done!
Also, I always warm up and stretch before a throwing session. That will save your shoulder too.
I've probably said more than what you wanted to hear, but maybe it'll help you. I hope my hard journey will make someone else's easier.