at the entrance to your stomach is a valve which is a ring of muscle called the lower esophageal sphincter (les). normally the les closes as soon as food passes through it. if the les doesn't close all the way or if it opens too often acid produced by your stomach can move up into your esophagus. this can cause symptoms such as a burning chest pain called heartburn. if acid reflux symptoms happen more than twice a week you have acid reflux disease also known as gastroesophageal reflux disease (gerd).
what is acid reflux disease?