In Danish would you express it as the equivalent of 'I have a blockage in my ear'? Sinead's answers are all good and perfectly correct but they sound a little I don't know, technical, I guess. I'm just thinking of what I would say if this were to occur to me and I would say: My ears are blocked with wax. Using a different structure.
Or even, I might just say 'I have wax in my ear.' It's understood what you mean when you say that.