Suggest Treatment For Upper Arm Pain

About two months ago I was scrubbing my back in the shower with my right arm up and over my shoulder,when suddenly there was a click in the tendons on the upper inside of the arm.I was able to bring the arm down to its normal position. Unfortunately ,after that incident, I have been having stabbing pains in the upper arm when I lift my arm sideways and in front. The pain radiates up over the shoulder into the side of the neck, and feels as if I have a bra strap that is too tight. As an eight-one year-old woman with major osteo-arthritis and numerous hip replacements, i have used a walker for seven years. I have had a similar less painful condition before, but usually after rest, it has gone away. I have to use my right arm to compensate for a limp on my left leg. My right arm has to work hard to enable me to walk. I have had some physiotherapy to no avail and also have now had X-rays and imaging done on the shoulder and upper arm. I would like to know if this injury will heal itself or perhaps the tests will show some damage which can be rectified. Apparently the joints are OK from the X-rays but I haven t had the results from the imaging yet. Perhaps you can give me some advice. Thanks.Marjory Sterry