If there is pain on the right side of the chest when breathing, the following possibilities are considered: 1. Pleurisy on the right side, such as right pleurisy caused by tuberculosis, can cause pleural effusion, and early breathing can lead to pain on the right side due to pleural friction. 2. Spontaneous pneumothorax, which can also cause pleural rupture, can also lead to pleural friction when breathing, thus causing chest pain on the right side. 3. The presence of malignant tumor involving the pleura can also cause pain on the right side when breathing. 4, if there is intercostal neuritis on the right side, it can also lead to pain when breathing. Therefore, patients need to improve the lung CT examination in time to clarify the diagnosis.