The phrase "stomach ache" refers to pain or discomfort in the stomach region. It can be caused by various reasons such as indigestion, gastritis, ulcers, food poisoning, constipation, gas, or even stress and anxiety. The severity of the pain can vary from mild to severe, and it may be accompanied by other symptoms like nausea, vomiting, bloating, or loss of appetite. A stomach ache is usually not a serious condition but it's always advisable to consult with a doctor if the pain persists or worsens.