I began having pain in my left shoulder - more the top and front part of my left arm than at the shoulder joint - about 3 weeks ago. It is now almost unbearable to lift my left arm with my elbow bent and lower arm parallel to my body. Now my right shoulder is beginning to have the same type of pain - and is sore to raise and lower. It feels muscular rather than a rotator cuff injury or anything. I haven t injured either arm. What on earth could cause this and how can I get it corrected?