It is possible that your son's earache is caused by a buildup of secretions from his nose and throat, which can travel to the middle ear through a small canal called the Eustachian tube. This can increase pressure in the ear and cause pain. It is suggested to try to clear out the nose and middle ear using a specific technique provided in a document. Additionally, using a nasal spray may help open up the nasal passages and Eustachian tube to help drain the secretions. If your son develops a fever or continues to experience ear pain in the next two days, it is recommended to seek medical attention.