Hi, I have pain in my left upper arm only in nights, normally before going to bed, it is not always, just once in a while, during the day I can do all my activities normally and do not feel any pain. Whenever I have this pain, I use Aleeve or Advil pills and next morning when I wake up, there is no pain at all and everything goes back to normal, until next time.Could you please tell me why I have this pain and how I can treat it. Thank you,