Sourness inside the throat may be due to laryngitis, gastroesophageal reflux disease (GERD) and other diseases. 1. Pharyngitis: when pharyngitis and other throat diseases occur, it will lead to local mucosal congestion and inflammation, which in turn causes an increase in local secretions, which may lead to sore throat, in addition to the combination of sore throat, cough and other symptoms. 2. Gastroesophageal Reflux Disease (GERD): Due to the relaxation of the lower esophageal sphincter and the decrease of the esophageal clearance ability, gastric acid and other gastric contents refluxed into the throat, which may cause soreness in the throat. In addition to acidity in the throat, symptoms such as heartburn, cough, and a foreign body sensation in the throat may occur. If you experience any of these symptoms or suspect that you have laryngitis or reflux pharyngitis, it is recommended that you go to the hospital promptly.