Undershirt pain chest tightness can be myocardial infarction, aortic coarctation, acute pericarditis, gastric perforation and so on. 1. Angina pectoris: the most common symptom is pain, the pain site can be the precordial area, the upper abdomen and even radiate to the jaw, back, etc., and the nature of the pain can be pressure-like. Gastrointestinal manifestations such as nausea and vomiting can also occur. 2. Aortic coarctation: the chest pain is very severe at the beginning, presenting tearing pain, often radiating to the chest, ribs, waist, etc., and there can be significant differences in the blood pressure of the upper limbs on both sides. 3. Acute pericarditis: there can be severe and persistent pain in the precordial region, which is aggravated by breathing and coughing. 4. Gastric perforation: severe epigastric pain can occur, and some patients’ pain can be manifested as precordial pain, which may cause peritonitis and shock if it continues to develop. Undershirt pain chest tightness and other symptoms can be caused by many diseases, if the discomfort, please consult a doctor in time.