I had "tennis elbow" some years ago from doing too much ironing in a short time. I have know otherss not diabetic, who have also had the condition . It is, as stated above a repetitive strain injury.
Alll these hings can normally be treated successfully with cortisone but will also correc themselves , in ime with rest. Depends how long you can wait.
Shoulders take much longer.
Isn't i strange how once you are diagnosed everything becomes due to diabetes, Before that it is osteo- athritis or merely age!