If patients always have chest tightness, shortness of breath, and can’t catch their breath, there are usually several factors as follows: 1. Cardiogenic factors, whether it is coronary atherosclerotic heart disease, unstable angina, myocarditis, pericarditis, infective endocarditis, hypertrophic obstructive cardiomyopathy, all will have clinical symptoms of chest tightness, shortness of breath, and even can’t catch their breath because of insufficient blood supply and oxygen supply to the coronary arteries; 2. Respiratory system 2, respiratory system diseases, chronic bronchitis, bronchiectasis, chronic obstructive pulmonary emphysema, chronic pulmonary heart disease, and even pulmonary hypertension, patients will have lack of oxygen due to insufficient arterial oxygen saturation, low partial pressure of oxygen and high partial pressure of carbon dioxide, and will also have symptoms and performance of chest tightness, shortness of breath, and breathlessness.