Chest pain is not a symptom you should ever ignore, for obvious reasons. Chest pain, as almost anyone knows, may indicate a cardiac problem. For this reason alone, if you have chest pain you should be evaluated by a doctor.
Definition of cardiac muscle. : the principal involuntary-muscle tissue of the vertebrate heart made up of striated fibers joined at usually branched ends and functioning in synchronized rhythmic contraction.
Cardiac muscle is a syncytium in which the cardiac muscle cells are so tightly bound that when one of these cells is excited the action potential spreads to all of them and allows succinct coordinated contraction of the heart.