Lymph node pain in the armpit should be considered to be caused by lymphadenitis or infection in the armpit. There are more causes of lymphadenitis, such as folliculitis or sebaceous cysts in the armpit, and secondary infection may involve inflammation of the lymph nodes in the armpit. You can take oral antibiotics, such as cephalosporin or penicillin such as amoxicillin, and the infection will be controlled, the lymph nodes will disappear, and the pain will also disappear. We cannot rule out the possibility of lymphoma or malignant tumor metastasis. It is recommended to go to the hospital for breast and axillary ultrasound examination in a timely manner, and puncture biopsy can be performed if malignancy is suspected.