Heartburn, or acidity, is a discomforting burning sensation in the chest, just behind the breastbone or in the upper abdomen. The pain often rises in the chest and may even radiate to the neck or throat.
It usually occurs after meals, when lying down, or at night while sleeping.
It is a major symptom of gastroesophageal reflux disease (GERD) in which the acid regurgitates to the esophagus. Heartburn is usually not associated with heart disorders; although the discomfort of heartburn can be confused with ischemic pain or vice-versa.