In a heart attack, time is heart muscle. The longer a heart attack continues on without treatment, the more damage is done to the heart. Chest pain is common in all heart attacks, but the most telltale sign of heart attack is not a sharp pain, but dull, squeezing pain across the chest. Radiation of the pain to the jaw or left arm is common as well. Other signs of a heart attack include nausea, vomiting, profuse sweating and a change in one's normal behavior or mental status.