There are several common causes of hidden pain inside the right side of the rib cage: first, intercostal neuralgia, also known as intercostal neuritis, which is mostly related to respiratory movements and can be aggravated when gasping for air. Second, pleurisy, which can also cause pain in the inner chest wall. This kind of pain is usually vague and needs to be examined in combination with chest x-ray. Third, some viral infections, especially the herpes zoster virus, which is neurophilic and can be distributed along the ribs and intercostal nerves. This kind of pain is only dull and painful in the early stage, and herpes appears only in the later stage. Fourth, the pain inside the right intercostal rib cage may be related to factors such as cholecystitis and gallstones.