I'm sorry that you have this lingering shoulder problem...

I believe there are ways to improve on the range of motion in your shoulder joint. That said, pain tolerance has to be factored in the therapeutic process.  In some cases, internal ailments such as pancreatitis might cause shoulder pain. Of course, in your case, it's clearly shoulder injury-related.

An experienced internal medicine specialist would give you helpful information. Anyway, my point is, there could be multiple sources of chronic shoulder pain.

All the best!