I had tinnitus and some hearing loss for a while, not surprising given my hobbies. Woke up one morning with pretty serious loss of hearing on the left side, which of course made the tinnitus worse (the explanation I got from the neurosurgeon in regards to tinnitus of this sort is that it's basically the brain trying to compensate for hearing loss by adding sound). Took a hearing test some months later, which showed significant hearing loss on that side (much more than I had imagined). The doctor didn't buy my explanation that it could be audio shock, and an MRI revealed a tumor. They caught it a little bit too late, so they had to carve through the inner ear to get it, so I'm deaf on one side now. But the tinnitus is still there.