Ahhh...the dreaded "itis". Let me share with you a story about one Yankee pitcher, more than half a century ago. His name was Ed Lopat, and his problem began immediately after the 1951 World Series in which he pitched and won two complete games. Suddenly he just couldn't lift his arm. Come the 1952 season and he couldn't do anything so he was put on the DL, or as they called it in those days "the shelf". He was out for a few months, and then he remembered an orthopedic surgeon whom he'd known in his White Sox days. He went out to Chicago, and the doctor examined him and told him that he had tendonitis in his left shoulder.
The doctor's prescription was radical in those days---I don't think they do it any more---but what he prescribed was a series of ten X-ray treatments. It worked---the way it had worked for Johnny Sain and a few other guys who had been after Steady Eddie to try it---and when he came back he was pitching better than ever. He racked up a 33-8 record after that, including what he continued to do to the Indians.
Lopat told me this story after I asked him where he'd been, I hadn't seen him all season. And then he said, "But enough of that. Tell me about the slider." (The year before, he had shown me how to throw it.) So I say to you, hang in there, get all the rest you can and take any treatment that might be prescribed, and when you get back into throwing, slow and easy does it. You'll be all right.