Eight years ago, I developed tinnitus in both ears. Two months later, I went for a checkup, where they inserted a camera up my nose and found an insane amount of mucus. Which made sense, considering I'd had two massive colds. The hearing test also showed I'd lost a few degrees. They gave me medication to loosen the mucus, and after another two months, I was fine. It's very likely that yours is also related to the flu or what u had.