The burning pain of acid indigestion — commonly called heartburn — affects an estimated 60 million Americans at least once a month and 15 million people daily, according to the American College of Gastroenterology. Most people experience the chest discomfort of heartburn (which, despite its nickname, does not affect the heart) after eating or when they lie down or bend over. It results from acid reflux — stomach acid that backs up into the esophagus, which is the tube that carries food from your mouth to your stomach. For some people, a bitter or acidic taste in their throat or mouth is an added heartburn symptom. Numerous foods and drinks have been linked to heartburn, but the specific trigger varies from person to person — spicy foods, citrus fruit or tomato products for some, chocolate or peppermint, fatty foods or alcohol for others. Experiencing heartburn more than twice a week could indicate a more serious condition — called gastroesophageal reflux disease (GERD) — that warrants seeing a doctor to ward off damage to the esophagus. But occasional bouts of heartburn are common, and while they can last for several hours, they usually are manageable with lifestyle changes (such as avoiding triggering foods, raising the head of your bed and not lying down for two to three hours after eating) and over-the-counter medications. One popular heartburn medication, Zantac (or ranitidine, in generic form) has been voluntarily recalled and pulled from drugstore shelves because of the presence of a potentially cancer-causing chemical, but the Food and Drug Administration says its testing has shown that the heartburn medications Pepcid, Tagamet, Nexium, Prevacid and Prilosec do not contain the chemical. One additional caution: If chest pain and pressure are ever severe, seek medical help right away; the pain could be a symptom of a heart attack, not heartburn.