Shoulder Pain

Hello, I am new here. I have been swimming for many years without any shoulder problems. Recently, I had a uppper back muscle pull which has migrated to my left shoulder. I took a week off from the pool. It feels fine now when I swim in the pool. But I can't sleep on my left shoulder when I sleep but still feel some pain but its not noticeable outside of the pool. I have swam over 13 miles since my week off without any pain in the pool. I went to a shoulder specialist and he recommended PT for 2 months while just kicking in the pool. I have looked at previous posts on this board regarding shoulder problems and most of them say that if you don't feel any pain while swimming then continue swimming. But if you do feel intense pain then stop and see a doctor. I know this is a continued topic on this board but just need some suggestions on if my doctor is wrong and just need to work on rotator cuff exercises and strengthen my shoulder muscles while doing the PT. Also, I think I can still swim but not to the intensity I was earlier in the year.