A lump under the ear without pain may be caused by sebaceous cyst, lymphadenitis, lipoma and so on. 1. Sebaceous cysts: mainly caused by the blockage of sebaceous gland excretory ducts, which can lead to the appearance of swellings in the skin of the affected area without painful symptoms. 2. Lymphadenitis: it can lead to enlarged lymph nodes and obvious lumpy swelling. In the early stages of the disease, some patients may have no symptoms of pain. As the disease continues to develop, the lymph nodes continue to swell and may be accompanied by obvious pain. 3. Lipoma: It is a common benign tumor of soft tissues, and the affected area may show painless lumps. There may be other reasons for this symptom. Patients are advised to seek medical examination as soon as possible to confirm the cause of the disease and provide targeted treatment.