Although not impossible, it would be rare for a young, healthy person to have underlying coronary artery disease. Predisposing factors for developing heart disease at such an early age would include diabetes, high blood pressure, hyperlipidemia, tobacco use, and family history of heart disease. Other conditions would include exposure to chest radiation and certain chemotherapeutic drugs. If you routinely are having chest discomfort during exertion associated with shortness of breath, nausea/vommitting, or light-headedness/fainting, I would suggest an evaluation by a licensed physician who can conduct a thorough history and physical. He/she can also evaluate for other potential causes of chest discomfort including GI, pulmonary, or problems related to the overlying skin/muscles.
Thank you very much for your response I will have to go back to the doctor again (cardiologist). I don't have any of the predisposing factors you listed but last year when I had a lot of anxiety my heart was beating hard and fast all the time for weeks and that led to heart pain including from chest exercises and later from jogging.