[Seabear]

Don't ignore it, it won't get better on its own. Rusnak is probably on the right path, rotator cuff. I have rehabbed both shoulders using an old book "The Seven Minute Rotator Cuff Solution". Small weights or bands, working all 4 of the rotator muscles starting very light with lots of repetitions. Within a few weeks the pain subsides, you add a bit more weight up to 7 or 8 pounds by the end of the regimen and your shoulder is back to or better than normal.