I am not sure what the cause of your chest pain is, but you are only 27 and the prevalence of disease in your age group is very low. The shortness of breath and/or wheezing may be pointing to a pulmonary cause, including perhaps asthma. This is a consideration, as it is several times more prevalent in your age group than obstructive atherosclerosis. I would suggest that you speak to a good general practitioner who can review your symptoms and decide where to proceed with diagnosis.
Let's try to clarify some things before the doctor gets here, so you can get the most of your question.
Are you telling us that you had an ECG and was diagnosed with severe heart disease? Or that you do not have heart disease? You will need more than an ECG for chest pain to complete a good evaluation, when the cause isn't obvious. What type of doctor are you currently seeing for this, and tell us again what he has told you?