You may experience heartburn, bitter taste in back of your throat, sore throat, and cough, sour taste in mouth and burning sensation in breastbone. Yes, these all are the symptoms of Acid Reflux, a common medical condition that occurs when the stomach acid – helps in food digestion – flows back into the esophagus. This backflow of stomach acid happens because the Lower Esophagus Sphincter (LES) becomes weaken or damaged, as it is a circular muscle that joins your stomach and esophagus and it is responsible for tightening the esophagus after the food passes to stomach. If it becomes weak and isn’t tightens properly then the acidic contents from the stomach move backward to the esophagus. Gastroesophageal Reflux Disease (GERD) is a chronic and severe form of Acid Reflux. The medical condition of GERD occurs when you experience Acid Reflux more often than twice a week which causes inflammation in the lining of esophagus.