Thanks for posting that. I'm about 2wks into the same ordeal.I went to see a Dr due to severe pain in my right shoulder as well about 7-8 yrs ago. Severe pain came up early on Sat after doing hundreds of pushups over a couple previous days of a "boot camp" class I was in. I believe I just overdid it, my fault.
After advil over Sat & Sun pain was mostly subsided by the time I had my appt a few days later. Dr diagnosed (in office) as rotator cuff injury, but wanted an MRI to be certain and to be able to diagnose how bad the injury was. Of course insurance had to approve MRI, and they denied it. Telling me to go to phys therapy for 6-8 weeks, then re-evaluate.
PT helped, but the issue has always dogged me since. Not bad enough to consider surgery, that is about all that can be done for it other than PT, exercise, & stretching. It has never been bad enough for me that I'd consider surgery.
I have had 3 broken collarbones as an adult (I was a MC racer in a former lifetime) and my shoulders since then are not aligned well. My right shoulder sits about 2 inches lower than the other while standing upright. I believe that is the root cause of my issue. What really has helped was stretching and weight lifting. Don't overdue it. But after awhile it did improve. Most recently, in a group exercise class, all these years later, I discovered certain arm exercises w/ 3 lb weights made a big improvement in strength & flexibility. After some time I started using 5# weights, then 7.5#. A very noticeable improvement all of a sudden all these years later.