Women’s armpit side pain, may be related to muscle strain, may also be due to folliculitis, armpit area superficial swelling hyperplasia and other reasons. 1. Muscle strain: if the muscle tension is weak, in the fitness exercise, due to the amplitude is large, or make the arm activity time is too long, is likely to cause the armpit area of the muscle strain, may cause armpit side pain. 2. Folliculitis: there are more sweat glands in women’s armpits, and the ventilation environment in the armpit area is not good, which is easy to induce folliculitis, resulting in red papules and pustules in the local skin of the armpits, which may cause pain in the armpits. 3. Superficial swelling hyperplasia in the armpit area: commonly seen in fibroma, lipoma and other benign swelling hyperplasia, along with the gradual increase in the size of the swelling, it may cause pain in the armpit, and may be accompanied by lumps of different sizes in the armpit. Women’s armpit pain may also be caused by other reasons, if the symptoms persist, you should consult a doctor as soon as possible to confirm the diagnosis of the cause, and then give targeted treatment.