The fact that you mentioned it just started recently and happens even off-bike is an good indicator that your bike isn't the one at fault, or at least not the only one..

What you're experiencing is pretty hard to determine - one has to consider types of food intake, last known activity prior to pain onset, environment factors, medications currently taking, etc.. I study/work in the healthcare area, and we take it seriously when someone is complaining of chest pain. So like the others mentioned, go see a doctor ASAP - your body is telling you something's wrong and it isn't advised to go self-treating like a DIY bike fix (no offense)..