My son is a a facility for the summer and his first max effort velocity throw caused pain in his whole arm. For two weeks now he's still having pain in the arm, he says his muscles hurt. At first he described it as his whole arm aching. At the facility they are calling it "sore arm" but I think it's more! What could he have injured that causes this type of pain? He saw the physical therapist who did not really give him a diagnosis for the arm. He is 20 yrs old.