Indigestion – Wikipedia

Indigestion, also known as dyspepsia or upset stomach, is a condition of impaired digestion. Symptoms may include upper abdominal fullness, heartburn, nausea, belching, or upper abdominal pain. People may also experience feeling full earlier than expected when eating.. Dyspepsia is a common problem and is frequently caused by gastroesophageal reflux disease (GERD) or gastritis.

https://en.wikipedia.org/wiki/Dyspepsia