Discomfrt left thorac rgn. Behavior?

From last two days, I am having a tolerable but continued pain on my left part of chest which includes muscles above rib cage, neck,shoulder, upper arm. It started out as a uncomfortable fast rate heartbeat and then the pain distributed to the nearby connecting body area when I tried to massage the muscles at that moment. Slowly the heartbeat decreased but there is a slight prolonged pain (like cramp) in the muscles of my left upper chest region (e.g. neck, shoulder, upper arm, and center part of left chest) I am an above average obese. 5 ft 9inch with 105kg wt. I have never had any history of chronic illnesses. Is this alarming? What should I do. Was this event normal or is it an example of cardiac malformed behavior?