So, the only way to know that you don’t have a blockage in the blood vessels to the heart, for absolute certain, is to have an angiogram. But, healthy people, without signs of heart disease shouldn’t have an angiogram, because there is a small risk associated, and it’s just not necessary. The best screening test for heart disease is either an exercise test, or a CT scan to look for calcium in the heart, but that should really be prescribed by your doctor, because it depends on a whole lot of other factors other than how you feel.