Sudden feeling of chest tightness and breathlessness are mostly seen in the following cases: Firstly, smelling pollen or paint etc. causes patients to be breathless, especially bronchial asthma patients will have sudden chest tightness and breathlessness. Second, spontaneous pneumothorax, spontaneous pneumothorax can suddenly appear chest tightness, breathlessness, according to the amount of compression area, chest tightness symptoms vary in severity, in serious cases, emergency rescue treatment is required. Third, cardiovascular disease, coronary heart disease, cardiomyopathy and other cardiovascular diseases can suddenly feel chest tightness and breathlessness, especially in patients with cardiac insufficiency. Sudden feeling of chest tightness and breathlessness should go to the hospital to do electrocardiogram, chest CT and other tests to clarify the cause.