Heart rate is normal but chest tightness and shortness of breath are usually caused by physiological reasons, heart diseases and lung diseases, etc. If they are physiological reasons, they do not need to be treated, if they are caused by heart diseases as well as lung diseases, they need to be treated. 1. Physiological reasons: if there is mental tension, indoor ventilation is not paid attention to, the body is too tired, etc., may lead to chest tightness and shortness of breath, at this time, the heart rate may be normal, there is no cause of disease, do not need to be treated. 2. Heart disease: due to the relative insufficiency of myocardial blood supply myocardial contractile dysfunction arrhythmia can cause chest tightness and shortness of breath, commonly found in hypertension, myocardial infarction, premature beats, arrhythmia, myocardial ischemia and other diseases. 3. Lung disease: due to lung dysfunction and respiratory dysfunction can cause chest tightness and shortness of breath, commonly found in pneumothorax, bronchial asthma, pulmonary embolism and other diseases. Among them, pneumothorax is seen in patients with emaciation or chronic obstructive pulmonary disease, alveolar disease, bronchial asthma attacks at night and in the early hours of the morning, pulmonary embolism patients with lower extremity venous embolism, or sedentary, long-term travel fatigue. If the chest tightness and shortness of breath continue to be unrelieved, it is recommended to go to the hospital in time for early and regular treatment.