In women, hidden pain under the armpit is often considered to be lymphadenitis, breast disease, metastasis of malignant tumors and other diseases. 1. Lymphadenitis: The lymph nodes in the armpit are rich in tissues, which are infected by bacteria to form lymphadenitis, which is often accompanied by local redness, swelling and hidden pain. 2. Breast diseases: such as breast hyperplasia, fibroma and other diseases, mostly occurring in both sides of the armpit area, or the upper part of the outer side of the breast. Most of the patients do not have obvious clinical symptoms, and occasionally see the symptoms of hidden pain in the armpits. 3. Metastasis of malignant tumors: such as breast malignant tumors or lung malignant tumors, the tumor can be seen to metastasize to the axillary lymph nodes in the late stage of the disease. In addition, boils and trauma in the armpit of women may also lead to hidden pain and discomfort here. It is recommended that if patients have symptoms of axillary pain, they should go to the hospital in time for a clear diagnosis and choose the appropriate treatment plan under the guidance of the doctor.