Often times in children it has to do with tonsils and adnoids. I had very bad adnoids that caused me to go deaf. They were removed in the summer between 4th and 5th grade. The inner ear drained and the infection was gone! I still have a bit of hearing loss in my right ear though.
I had my tonsils and adenoids out , so that is not the issue.
The swollen adnoids close off the Eustachian tubes causing fluid to build up and infection often follows. Might be something to look into. Sadly many Dr.s do not believe things like this cause problems in adults...