Regarding muscles pains in both hands.

Hello doctor...my father is suffering from severe muscle pain in his both upper hands...and at muscle joint point's.due to this he can't raise  His hands parallel to head.  He is taking the pills from neurologhy prescribed...and getting physiotherapy too...for hands...But still he is suffering from(like fiericing needle pain type)..one of the orthopedic doctor said they will give a injection at arm joint and rotate his hand...parallel to his head... My qntns is ...is it safe to to have that injection? Where as We want to go for medices.. .And he is Diabetic ...too... And he has pancreatic problem...          we are totally confused about...which doctor we have to consult about this problem?will u please suggest me Best specialist doctor...