text: <unk>  is defined as painful swallowing. It is caused by various medical conditions. It should not be confused with dysphagia, which is difficulty in swallowing. Common causes of<unk>  are throat infections, foreign body, acid reflux disease, tumors, or injuries which may lead to difficulty in swallowing due to disturbing pain.<unk>  is a word with Greek origin. There is no established system for the classification of<unk> . However we can classify them according to causes to approach the area of involvement. The pain in swallowing is induced due to conditions causing stimulation of sensory nerves innervating esophagus and pharynx. Several diseases, such as, Achalasia cardia, Esophageal cancer, Myasthenia gravis, Scleroderma, Tonsillitis, upper respiratory tract infections, Zenkers diverticulum and gastroesophageal reflux disease have<unk>  as one of their presenting symptoms and thus, it is essential to differentiate these diseases from one another.
option_0: Odynophagia
option_1: Aerophagia
option_2: Dysphagia
option_3: Borborygmus
option_4: Trench mouth
option_5: Spasmodic dysphonia
option_6: Excessive tearing
option_7: Drooling