The phrase "stomach issues" refers to any problem or discomfort related to the stomach, such as indigestion, heartburn, bloating, gas, nausea, vomiting, diarrhea, constipation, and other gastrointestinal symptoms. These conditions can be caused by a variety of factors including diet, stress, medications, infections or underlying medical conditions such as irritable bowel syndrome (IBS), ulcers, or gastroesophageal reflux disease (GERD).