The most common problem in gastroenterology is gastroesophageal reflux. This means the acid and digestive juices produced in the stomach, which tolerates this stuff, gets up into the esophagus, which decidedly does not. The pain associated with reflux is called heartburn, which many people call “gas.” Gas has an undeservedly bad reputation.
http://www.news-press.com/story/opinion/columnists/john-agnew/2016/03/17/heres-bad-news-heartburn-sufferers/81907244/
Here's bad news for heartburn sufferers