Heartburn and burning sensation in the middle of the chest may be caused by gastroesophageal reflux disease (GERD), chronic gastritis and gastric ulcer. 1. Gastroesophageal reflux disease (GERD): a chronic disease in which the contents of the stomach and duodenum flow back into the esophagus, causing damage to the esophageal mucosa. Its main manifestations are heartburn, burning sensation in the middle of the chest, usually accompanied by reflux, chest pain, belching, nausea, vomiting, dysphagia and other symptoms. 2. Chronic gastritis: refers to chronic inflammatory lesions of the gastric mucosa. It can also lead to heartburn, burning sensation in the middle of the chest, usually accompanied by epigastric discomfort, fullness, loss of appetite, acid reflux, belching, nausea, vomiting and other symptoms. 3. Gastric ulcers: Ulcers on the inner wall of the stomach can also lead to heartburn, burning sensation in the middle of the chest, usually accompanied by regular epigastric pain, bloating, belching, anorexia, acid reflux, nausea, vomiting and other symptoms. There are many other causes of heartburn and burning sensation in the middle of the chest, which should be taken seriously, and prompt medical attention should be paid to identify the cause of the disease and further treatment or therapy as prescribed by the doctor.