My 12 year old son fell on his left arm during a basketball game, after he was tripped. He said a sharp pain radiated through his arm. It is a little swollen, but he is able to move his arm and wrist. When he rotates his arm left or right, it is painful (7 out of 10, 10 being the worst). We have been icing it, but was wondering if we should take him to the emergency room.