I am a 25-year-old man, and the weather is very hot. I always feel chest tightness and shortness of breath, and sometimes I can't breathe. I still doze off and breathe, mainly sitting. ...

You belong to dyspnea, which can be divided into five categories: 1, respiratory, such as asthma and pneumonia. 2. Cardiogenic, such as congenital heart disease and heart failure; 3. Toxicity, such as diabetic ketoacidosis and phenobarbital drugs; 4. Blood, such as anemia and methemoglobinemia. 5, mental and neurological factors, if the cardiopulmonary examination is normal, (that is, chest tightness without organic lesions): people often feel chest tightness and fatigue when they stay in a room with closed doors and windows and no air circulation for a long time, or encounter some unpleasant things, or even argue with people, or in a low-pressure climate. After a short rest, open the window for ventilation or breathe fresh air outdoors, relax and adjust your mood, and you will soon return to normal. Chest tightness like this can be said to be functional chest tightness. There is no problem with chest radiograph and electrocardiogram. It is functional chest tightness, which is caused by tension and anxiety. There is no need to be nervous, relaxed and have a rest. Most people will be fine in three months.