You’ve just eaten a big meal and feel a burning sensation in your chest. Your first thought is heartburn and you are probably right. But experts say there’s a good chance the chest pain is caused by reduced blood flow to the heart (angina) or an actual heart attack.

Heart burn, angina and heart attack may feel very much alike, according to the Mayo Clinic. Even experienced doctors can’t always tell the difference from your medical history and a physical exam. That’s why, if you go to the emergency room because of chest pain, you will immediately have tests to rule out a heart attack.

Of the over eight million emergency room visits for chest pain each year, severe heart burn accounts for half of the cases, according to Harvard Health Publishing.

Heartburn is a common symptom of gastroesophageal reflux disease (GERD), often called acid reflux. Acid from the stomach bubbles up, causing pain burning just behind the breastbone.

Chest pain caused by angina or an actual heart attack have symptoms of tightness, constriction, or pressure rather than the burning feeling caused by heartburn.

“Chest discomfort brought on be exercise is more likely to be a heart related problem,” says Dr. Michelle O’Donoghue, cardiovascular specialist at Harvard-affiliated Brigham and Women’s Hospital. But she warns that you can also have angina that’s not related to physical activity so if you have any symptoms you are not sure about, see a doctor. Call 911 immediately, she says, if you feel chest tightness, have trouble breathing, break into a sweat, turn pale or become very weak.

The Mayo Clinic notes that “textbook” heart attacks involve sudden, crushing chest pain and difficulty breathing, often brought on by exertion. However, many heart attacks don’t happen that way and the signs and symptoms can vary greatly from person to person. In fact, heartburn itself can accompany other symptoms of heart attack.

Typical symptoms of heart attack include:

• Tightness, pressure, a squeezing feeling, stabbing or dull pain often in the center of the chest
• Pain that travels to the shoulders and down the arms
• Irregular or rapid heart beat
• Cold sweats or clammy skin
• Lightheadedness, weakness or dizziness
• Nausea, indigestion, and sometimes vomiting
• Symptoms brought on with physical exertion or extreme stress
• And typical symptoms of heartburn include:
• Burning chest pain that begins at the abdomen and travels up into the chest
• Usually occurs after eating or while lying down or bending over
• May awaken you from sleep, especially if you have eaten within two hours of going to bed
• Is usually relieved by antacids
• Pain that moves up toward your throat but typically doesn’t radiate to your shoulders, neck and arms
• May cause a sensation that food is coming back into your mouth or be accompanied by a bitter or acidic taste at the back of your throat

Experts advise that you seek medical help immediately if you are not sure what is causing your chest pain.