All babies cry. Most babies cry a lot. Some babies are more easily comforted, others can routinely work themselves into a frenzy. Of course it sends your heart racing. That's Mother Nature's way of insuring that the human race survives.
Colic is traditionally defined as 3 hours or more of daily crying, at least three times a week. 20% of babies are officially diagnosed with colic. But you could think of colic as simply crying that goes on and on and does not seem to have a cause.