Sudden pain in the armpits is considered to be related to trauma, enlarged lymph nodes, sweatshirt, frozen shoulder, breast hyperplasia and other factors, and need to go to the hospital for further examination to clarify the cause of the disease, and then timely treatment. 1. Trauma: generally due to the axilla by more intense impact or extrusion caused by the phenomenon of armpit pain, trauma may also appear fever and other symptoms. 2. Enlarged lymph nodes: usually due to the proliferation of lymph nodes, causing pain in the armpits, swollen lymph nodes usually appear red, swollen, fever and other symptoms. 3. Sweatitis: it may be due to inflammation stimulation, which leads to poor secretion of sweat glands, resulting in localized blockage, causing underarm pain. Sweatitis usually presents with symptoms such as fever and general malaise. 4. Frozen shoulder: usually due to frozen shoulder, resulting in ligaments around the shoulder joint, the joint capsule adhesion contracture, caused by the phenomenon of underarm pain, frozen shoulder may also appear pressure pain and other symptoms. 5. Breast hyperplasia: female breast hyperplasia will be congested and swollen, stimulate the nerves, and will feel the pain pulling toward the armpit. If the phenomenon of underarm pain, should pay attention to rest, appropriate participation in physical exercise, pay attention to warmth, so as not to catch cold.