Whenever I throw a baseball my arm hurts in three places what could I do to prevent it from hurting anymore?

I am a pitcher for my basball team and I threw my arm out pitching. Whenever I throw my arm hurts in three places, right under my bicep, behind my shoulder, and in front of my shoulder. I wanna know what I can do to prevent this injury. I apply ice every night and before games and it still hurts.