Beth,
Up until now you have had much the same surgery as me. I also had the painful arm while raising it above my head. Hair washing was difficult. Someone told me it could be that my arm was raised behind my head during the long operation. Went to a few sessions which I organised privately with a physio and in the end he suggested it would come good by itself. One day a few weeks late I just realised I was washing my hair with both arms up without a problem. Best wishes for the rest of your treatments.