Chest pain is one of the most common symptoms encountered by doctors working in acute, internal, and pulmonary clinics. In the United States in 2006, 10 percent of all visits to the emergency room were caused by diseases of the respiratory system, and chest pain was the most common symptom. The most common situations that can cause chest pain with an emphasis on their diagnosis and early treatment are chest infections, pneumothorax, pneumomediastinum and tumors affecting the pleural cavity.