The pain below the left posterior rib can be caused by several reasons: first, costochondritis, patients with costochondritis can have pain below the rib cartilage, which requires early examination and examination, early oral cartilage nourishing drugs and physical therapy. Second, herpes zoster, in the early stage of herpes zoster can have pain under one side of the rib, often stabbing, vague pain, after 1-2 weeks of incubation period can have clusters of herpes, then early diagnosis and early treatment to the dermatology department. Third, abdominal diseases, when there is enteritis or chronic colitis in the abdomen, there can be pain deep behind the left lower ribs, then early examination of colonoscopy and abdominal CT, ultrasound to diagnose and treat.