Throat discomfort, chest pain and belching commonly result from overeating, drinking alcohol while eating and consuming greasy or spicy foods. Taking certain types of pills without drinking sufficient water also can cause these symptoms. When you swallow something too large, too hot, too cold or too rapidly, the esophagus reacts.
http://bismarcktribune.com/lifestyles/health-med-fit/body-reacts-to-overeating-by-belching/article_897d833b-4ccd-5085-8957-ec4d9b8aea0d.html
Body reacts to overeating by belching