I am a 16 year old girl , and just this morning I started having chest pain in the left side of my chest, below my collar bone . I also have pain in my upper back on the left side. My chest hurts when I breathe . However, sometimes the pain is gone or barely noticeable. At one point today, for about 30 seconds, the pain became much more severe than it had been all day, but then returned to normal. Is this something I should see a doctor about? Or should I wait to see if the pain subsides?