My shoulder crunches when I raise my arm above my head and clicks and crunches when I move it. I am also getting a dull ache in the shoulder every day which is worse at night. My shoulder feels weak and pops out of position and there is also sometimes a slight ache down my arm. Since I am training to be a dance teacher this is uncomfortable for me. Do you know what the cause may be and what the best cause of action is for me?