It really is hard to say and certainly not my place to diagnose your symptoms as "cardiac related" EKG's are really not the best tool to rule out heart disease. The best way to do this is to go through stress testing and echocardiogram to see how your heart and valves are functioning.
Do you have any risk factors that put you at an increased risk of heart disease?
Generally, if you can pin point the area of your chest that hurts it's not cardiac in nature. Also, sharp pains are not generally cardiac either, although they could be. Cardiac pain generally is a pressure, fullness or a crushing pain in your chest that lasts more than a few minutes. The pain may radiate to your back, neck, jaw, shoulders and arms, especially your left arm. Other signs and symptoms may include shortness of breath, sweating, dizziness and nausea. All, some or none of these may accompany your chest pain.
Hope this helps,
Jon