Stomach acid radiating up your throat is a sign of heartburn and it can last for a short while or even up to a few hours. It tends to occur more right after eating, bending over, or lying down. There are many more signs and symptoms that indicate or possibly may indicate a heart attack. Symptoms range from shortness of breath, sweating, episodes of chest pain, pressure and/or fullness that can last for more than just a few moments, fainting, nausea, and even pain that can go from your chest to your shoulders to your arms and back and even to your teeth and/or jaw. The best way to find out for sure if it's just heartburn or a heart attack is to go to your nearest emergency room just to be safe.