Men’s left side pain below the rib cage can have the following causes: first, herpes zoster, in the early stages of herpes zoster, there can be pain below the rib cage on one side, after 1-2 weeks of incubation period, there can be clusters of herpes, this time to go to the dermatology department for early diagnosis and early treatment. Second, intercostal neuralgia, intercostal neuralgia can have pain at the intercostal nerve below one side of the rib cage, often radiating pain, vague pain or stabbing pain, this time to early investigation, diagnosis, early nerve nutrition and closure treatment. Third, dermatomal neuritis, when there is chronic inflammation of the dermatomal nerve below the rib cage on one side, it can lead to pain with numbness in the dermatomal nerve innervation area, which requires early physical examination, early diagnosis, early nerve nutrition and physical therapy.