Acid reflux disease occurs when stomach acid regularly escapes into the esophagus. Its most common symptom is heartburn, a burning sensation in the esophagus. In addition to heartburn, acid reflux can cause a number of other symptoms, including: Regurgitation – a bitter or sour acid taste at the back of your throat Belching or Bloating Early satiety – feeling full too soon Nausea and/or vomiting