Armpit generally refers to the armpit. Pain in the armpit attached to the arm may be due to trauma, frozen shoulder, herpes zoster, localized infections and other diseases, which should be consulted promptly. 1. Trauma: armpit and arm pain can be caused by violence, over activity, stretching, etc. Patients mostly have a clear history of trauma, combined with local MRI and medical history, the diagnosis is usually not difficult. 2. Frozen shoulder: this disease is an inflammation of the soft tissues around the shoulder joint, and the clinical manifestations may have some variability. Some patients may have the above symptoms, which are related to the stimulation of inflammation and neuroradiation pain. It is also usually accompanied by activity limitation, such as the inability to complete the combing movement. 3. Herpes zoster: This disease can also occur in the armpits and arms, and typical lesion changes can usually be seen. When the inflammation involves the nerves, the nerves become edematous and degenerated, resulting in severe neuralgia, which is mostly burning and cutting in nature. 4. Infection: localized infections in the armpits and upper limbs can lead to pain, related to the stimulation of inflammatory substances, common infections are skin cellulitis, lymphadenitis and so on. If the pain in the armpit with the arm is not significantly relieved after resting, you should consult a doctor in time to check the cause of the disease and then targeted treatment.