The main causes of pain in the armpit when pressed include the following: first, consider that it is caused by soft tissue injury in the armpit, mostly due to strenuous lifting of the upper limbs or failure to warm up for activities such as pull-ups, resulting in strain on the soft tissue of the armpit muscles and thus causing pain in the armpit when pressed; second, consider that it is due to swollen lymph nodes in the armpit, reactive hyperplasia, inflammation causing pain in the armpit, the armpit There are a large number of lymph nodes in the armpit, due to local or systemic inflammation, the inflammation of the lymph nodes in the armpit will cause redness, swelling and pain in the armpit, and pain will occur after pressure; thirdly, female comrades also need to consider the pain caused by the axillary lobe and lobular hyperplasia of the breast in the armpit. Ultrasound of the breast and ultrasound of the armpit can reveal the hyperplastic glands. There are many reasons for armpit pain, and if the pain is severe, you need to go to the hospital in time.