Hello First off, thank you for taking the time to read my message. I am 18 years old and lately, my heart feels like its being poked constantly. I am also very short of breathe and walking up a set of stairs feels like a marathon.The location of the pain originates on the left breast, just above the nipple. The pain is interior and throbs from time to time.I am really concerned and am not sure what to do. I can't go to the doctor anytime soon due to work, but I want to get checked out immediately. What do you think it could be and who would you advise seeing first? A family doctor, or go straight to ER?