I too had chest pain, and they found that I had GERD. I had all kinds of cardio work done and finally was sent to a Gastroenterologist (sorry for spelling, unsure) and they found that I was releasing a great amount of acid. My esophagus was/is inflamed. I greatly suggest you dig deeper than just a Cardiologist.
Not to be rude but that is not the ONLY solution. It may be part of the solution but it is not the only solution. You could have something serious going on, or something as simple as taking medicine for GERD. Whenever someone is having chest pain, it should never be taken lightly. Please see your doctor hun. Do not listen to those who tell you that losing weight is the only soltuion.
Sounds to me like an acid reflux type of thing - when you exhale, the diaphragm pushes stomach acid up into your esophagus, and it feels like a heart problem, but in fact it is the result of the acid burning the flesh in your esophagus. Try a Tums for temporary relief, but loose weight - the extra fat in your abdomen presses up on your stomach to "burp' up the acid when you exhale - that is what I have found anyway! :-)
get a diet. lose weight! thats the only solution my dear.
It could have something to do with your lung or heart. You should see a doctor and let them know what is going on. From there they can do an EKG, blood work and an Xray to make sure this is not something serious. Hope you find the answers you are looking for. good luck and take care.