Pain at the junction of armpit and breast is recommended to choose to consult a mammology department because breast hyperplasia often causes localized breast or ipsilateral armpit, or ipsilateral back and upper arm distension, discomfort, and breast hyperplasia is related to breast hyperplasia, which causes localized distension and discomfort on the outer side of the breast, armpit, or shoulder of the forearm. In addition, because breast lumps or breast malignant tumors are most likely to metastasize to the axillary lymph nodes, a lump in the breast, if malignant, may cause swelling of the ipsilateral axillary lymph nodes or discomfort in the ipsilateral axilla. You need to go to the regular hospital for formal examination to rule out the possibility of malignancy of breast lumps and swollen lymph nodes in the axilla, if ruled out later, there is no need to cause too much worry.