Hello, Pneumothorax or angina pectoris to be ruled out. As per the given history, your friend seems to have developed symptoms suggestive of pneumothorax. A pneumothorax occurs when air leaks into the space between the lung and chest wall. This air pushes on the outside of your lung and makes it collapse. In most cases, only a portion of the lung collapses. Another possibility is angina pectoris. Angina pectoris is the chest pain or discomfort due to coronary heart disease. It occurs when the heart muscle doesn t get as much blood as it needs. It usually happens because one or more of the heart s arteries is narrowed or blocked, also called ischemia. In view of the above, your friend should be taken to the hospital immediately and certain lab tests such as ECG and chest x-ray to be taken to rule out these conditions. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Mohammed Taher Ali