If there is a swelling under the ear with pain, it may be caused by mumps. Mumps occurs when the body’s resistance decreases and is caused by a viral infection that leads to an enlargement of the parotid gland and pain, usually below the earlobe, with a lump about one or two centimeters in size and painful when pressed. Since it is near the temporomandibular joint, the patient may have difficulty opening the mouth and the pain on the affected side when chewing after eating is also very obvious. Antiviral treatment is needed, such as oral oseltamivir or intravenous ribavirin, etc. If there is pain behind the earlobe with enlargement, it may be caused by inflammation of the lymph nodes, mostly due to bacterial infections such as Staphylococcus aureus or Streptococcus hemolyticus. Oral antibiotic treatment, such as cefixime, is required. Generally, the inflammation can subside and the pain can be relieved in about 7-10 days of treatment.