How long were you rowing? Rowing is rather tricky because to do it healthfully you really need good form. When I first started exercising, I loved rowing but could not continue because it threw out my back.
I learned it was also partly due to poor posture.
Also, I had a debilitating form of tendinitis and overuse syndrome in my twenties. I went to all sorts of renowned specialists and was given all sorts of anti-inflammatories. Two years later I somehow wound up at a physical trainer/ ex-basketball coach who actually measured my strength and advised me to start working out and increase muscle mass. I did. Although it took four or five years of faithfully going to the gym weight lifting conservatively, I did completely heal and got stronger. Yes, it did take years to heal in my case. It's not a quick fix. But it is a real fix that taught me that you must take care of your body. To this day I exercise regularly and am stupidly healthy. I am 53 and eat a lot of chocolate pie.
You might look up what sort of injuries rowers usually have and see what physical therapy is usually prescribed. Whatever is happening to your body is probably cumulative?
https://www.amazon.com/Treat-Your-O...eway&sprefix=mckenzie+shoulder,aps,146&sr=8-1 Robin McKenzie is a physical therapist who has written books on pain in the shoulder, knee and back. I strongly recommend them. They have invaluable exercises that are mostly stretches and not difficult. At the very least they will increase your knowledge of how the body works.
Good luck to you. 47 is young. With patience, you can achieve a lot.
o7