The right side of the chest hurts when you breathe hard may be pleurisy, spontaneous pneumothorax, pericarditis and other diseases. 1. Pleurisy: the most common symptoms are chest pain, chest tightness, accompanied by coughing, coughing up sputum, shallow and fast breathing, and in severe cases, dyspnea, chest pain is often aggravated by coughing or deep breathing. It is mainly seen in infectious diseases, tumor diseases, connective tissue diseases and metabolic diseases. 2. Spontaneous pneumothorax: the typical symptoms are chest pain, dyspnea and irritating cough, and the chest pain is often aggravated by coughing or deep breathing. When the lung tissue and the pleura of the visceral layer rupture spontaneously, air enters the pleural cavity, which will lead to the accumulation of gas in the chest cavity to form spontaneous pneumothorax. 3. Pericarditis: mainly manifested as chest pain, and the chest pain is often aggravated by coughing or deep breathing, and some patients manifested as dyspnea, irritability or even shock. Viral infection is the most common cause. Right side chest pain when breathing hard may also be other chest diseases, such as chest trauma. When the right side of the chest hurts when you breathe hard, you should go to the hospital at the first time.