I am a 36 w/f I have a constant dull pain in my right upper chest about even with my armpit almost directly inline with my nipple (Just to give an exact location), that feels like it goes straight out through my back at the exact location. The pain radiates down to my right under arm and stops approximatly 3 inches from my elbow. The pain transitions from dull to stabbing when deep breathes are taken, when I move my arm a certain way and when lying down. This has gradually gotten worse over the past week. Please advise if I should go to the ER or what the possibilities of causes could be.