It's the middle of the night or maybe the beginning of a busy workday when you suddenly feel pain in your chest. You may try to ignore it at first, but the pain has you scared and worried. Could you be having a heart attack? Should you go to the emergency room?

Chest pain is one of the most common reasons people call for emergency medical help. Every year emergency room doctors see nearly 5 million Americans for this symptom.

Chest pain doesn't always signal a heart attack. Often it's unrelated to any heart problem. But even if the chest pain you experience has nothing to do with your cardiovascular system, the problem may still be important — and worth the time spent in an emergency room to have it evaluated.