Ear pain in 3-year-old babies may be caused by cerumen embolism, or it may be caused by acute otitis media, otitis externa and other disease factors. 1. cerumen impaction: cerumen refers to the secretion from the external ear canal. When the secretion from the external ear canal is high and cannot be cleared in time, cerumen will accumulate in the external ear canal, which will easily lead to hearing loss, pain in the external ear canal, and ear swelling. 2. Acute otitis media: acute otitis media is mainly caused by inflammation of the middle ear due to infection of the mucous membrane of the middle ear by bacteria such as Staphylococcus aureus, etc. Babies under the age of 3 years old belong to the susceptible group, and are often characterized by ear pain, fever and hearing loss. 3. Otitis externa: the baby due to malnutrition caused by the decline in resistance can trigger otitis externa, the phenomenon of ear pain. Due to ear pain, babies will cry to express their discomfort, which may affect their sleep quality. It is recommended to take your baby to the hospital for a relevant examination to clarify the cause of the disease and carry out appropriate treatment under the guidance of the doctor.