Heartburn or pyrosis is a painful or burning sensation in the esophagus, just below the breastbone usually associate with regurgitation of gastric acid. The pain often rises in the chest and may radiate to the neck, throat, or angle of the jaw. Heartburn is also identified as one of the causes of chronic cough, and may even mimic asthma. Despite its name, heartburn actually has nothing to do with the heart. It is so called because of a burning sensation of the breastbone where the heart is located although some heart problems do have a similar sensation to heartburn. Compounding the confusion is the fact that hydrochloric acid from the stomach comes back up the esophagus because of a problem with the cardiac sphincter, a valve which misleadingly contains the word "cardiac" (an adjective referring to the heart) in its name.