Viral pharyngitis is the most common cause of a sore throat. Pharyngitis is inflammation of the throat. It can also be caused by bacteria, irritants, or as a symptom of another disorder, like GERD. Each type of pharyngitis, and thus each cause of sore throat, may require particular treatment. However, most mild sore throats simply clear on their own, though there are a number of things you can do to ease the pain and discomfort.