Is there a for cure or an exercise to ease the pain of tendinitis in the shoulder?

[Ruhtranayr]

The clinic diagnosed my mother with tendinitis in her shoulder. He gave her a sling and said don't use it for a week. She didn't listen. Now it's worse and she's in a lot of pain. She refuses to go back to the doctor. My mother is too stubborn and says she has 'no time' for physical therapy. Well her shoulder is giving her excruciating pain.

Is there an exercise like yoga or something that will help her?

Or does she just need to stop using it?