For patients with pain under the arm fossa: First, it is seen in lymphadenitis of the axillary area, especially after the onset of lymphadenitis, which can cause obvious enlargement of lymph nodes and pain and pressure pain under the axillary area, and sometimes can be touched obvious enlarged lymph nodes. Second, see in folliculitis, especially the axillary area in the arm will lead to closed, which will lead to the pore area can not expand, resulting in the secretion of the accumulation of hair follicles, causing the situation of folliculitis, will also lead to pain symptoms under the armpit. Third, in the middle-aged and elderly people appear in the shoulder joint parts of the bone degeneration and hyperplasia, if the hyperplastic bone stimulates the shoulder joint below the ligament joint capsule, will also appear under the armpit pain symptoms appear.