What is pneumothorax? what causes it?

Collapsed lung: Potentially life threatening disease! Many reasons. Check with your lung specialist and discuss the need of a CT scan of the chest and lungs. Good luck.

Pneumothorax: A pneumothorax is air that is trapped between a lung and the chest wall. The air gets there either from the lungs or from outside the body. http://patient.info/health/pneumothorax-leaflet

Trapped air: A pneumothorax is air that is trapped next to a lung. Most cases occur 'out of the blue' in healthy young men. Some develop as a complication from a chest injury or a lung disease. The common symptom is a sudden sharp chest pain followed by pains when you breathe in.