Hey doc, I have been having some mild chest pains, not all the time but when it feels like pressure in the center off my chest I crack my sternum to releive the pain. It s been going on for about 2-3 months, I am a 21 year old male, athlete (running,basketball) no history of heart problems or any major problems. I smoke and chew tobacco, since I was 18. More than anything it feels like a pulled muscle in my chest and when I can t releive the pressure by cracking my sternum i feel more discomfort while bending my head down or stretching my arms across my body... Can you help me out??