It is important first to distinguish between a sore throat
and painful swallowing. A "sore throat" is a common complaint in people that are afflicted by an upper respiratory infection, usually caused by viruses. The sore throat may certainly cause some pain with swallowing, but this typically affects only the part of the throat directly behind the tongue. This type of pain is usually transient and clears up within several days.
If swallowing causes pain that is located further down towards the chest, then the list of causes is distinct from those causing a typical sore throat. This sensation of pain is typically due to irritation of the lining of the esophagus (the tube that leads from the mouth to the stomach); this can be due to reflux of acid produced in the stomach, infections (typically yeast or viruses such as herpes), radiation therapy exposure, or poor passage of pills (i.e. pill esophagitis). If a patient is truly experiencing this type of pain while swallowing liquids and solids, then it would be advisable to see a gastroenterologist
, who may choose to perform an endoscopy (where a long skinny tube with a camera is placed into the esophagus to visualize the problem).