Rib pain under the left chest and enlarged lymph nodes in the neck may be related to costochondritis, lung malignancy, stomach tumor. 1. Osteochondritis dissecans: Osteochondritis dissecans is caused by bacterial infection, manifested as local pain, when invading the lymphatic tissues in the neck, it will cause swelling of the lymph nodes in the neck, resulting in discomfort in the neck, and can be treated with oral medication, such as ibuprofen capsules, amoxicillin capsules, etc., to reduce inflammation and relieve pain. 2. Lung malignant tumors: lung malignant tumors may have no discomfort symptoms in early stage, and when they are found, they are already in advanced stage, manifesting as pain in the left lower chest ribs and enlarged lymph nodes in the neck. 3. Stomach tumor: malignant tumor of stomach can cause pain in the left lower rib cage, accompanied by nausea, poor appetite and other symptoms, the most common lymphatic metastasis is the lymph nodes in the neck, which is manifested as enlarged lymph nodes in the neck. There are many reasons for pain and enlarged lymph nodes, and if oral medication does not relieve the pain, you should consult a doctor in time to find out the cause of the disease and treat the symptoms, and you should not blindly use medication on your own.