Huh, I'm reading and looking up these words you guys are saying and it is starting to look exactly like the symptoms I have been having with my own right shoulder! I feel like a giant gaping rabbit hole just opened up next to my desk.

We're discussing calcific tendinitis (https://radiopaedia.org/articles/calcific-tendinitis?lang=us). If you think you have it, you can see a doctor and consider shoulder radiographs to start.