Heartburn is the common term used to describe a burning sensation in the upper chest. Although it is called heartburn, it is not related to the heart at all.
Heartburn is caused by stomach acid moving back up the esophagus, the tube that carries food from the mouth to the stomach. Occasional heartburn is usually self-treated with nonprescription antacids or OTC acid blockers.
A doctor should evaluate frequent, persistent heartburn not relieved by nonprescription products or heartburn with other symptoms, such as difficult or painful swallowing, hoarseness, nausea, or vomiting. These symptoms could be a sign of GERD (gastrointestinal reflux disease) or another condition treated with prescription medications.
Source: US Pharmacist