Causes of fullness in the throat include allergic reactions, anxiety, indigestion, and reactions to medications, according to WebMD. Rare conditions that can also cause feelings of fullness in the throat include small intestine cancer and Budd-Chiari syndrome.
Allergic reactions, including drug allergies, are common causes of throat fullness, notes WebMD. Anaphylactic shock is a severe allergic reaction in which a person experiences severe breathing trouble along with tightness in the throat.
Issues with the digestive tract and stomach, such as gas pains, gastroenteritis and intestinal infections, frequently cause feelings of fullness in the throat, reports WebMD.
Other conditions that could cause fullness in the throat are gallstones and supraventricular tachycardia, according to WebMD.