Pain in the lungs occurs in most pathological conditions. Because of the large number of abundant nerve endings in the lungs, pain in the lungs can occur to varying degrees when the nerve endings are stimulated in various ways. More common clinically are inflammatory reactions, such as bronchitis and pneumonia, bronchiectasis combined with severe infection, bronchopleural fistula, and pleural effusion and pleurisy, which can cause a large amount of inflammatory secretions to exude and irritate the peripheral nerves of the lung causing pain. It is also seen in malignant lesions such as bronchopulmonary carcinoma and alveolar cell carcinoma, which can damage the mucous membrane of the lung and cause lung pain due to stimulation of the peripheral nerves in the lung. It is also seen in plant nerve dysfunction and intercostal neuralgia caused by intercostal neuritis of the chest wall, which can also cause pain in the lungs.