Acid reflux is a fairly common condition that occurs when stomach acids and other stomach contents back up into the esophagus through the lower esophageal sphincter (les) the les is a muscular. Acid reflux upset stomach pain. Common symptoms of an upset stomach and indigestion include: heartburn, or acid reflux; nausea; bloating; gas; belching, sometimes bringing up bitter or foul-tasting fluid or food; farting; bad.
acid reflux upset stomach pain
