I’m afflicted pretty badly by tinnitus, you have my sympathies. I went more or less completely deaf in my right ear which really compounded it. I also have hyperacusis which is the intolerance to certain sounds that you describe. All sorts of stuff can cause temporary tinnitus – even vitamin deficiencies (how’s the diet?). Tired, too much booze, excessive noise (obviously), viruses.
I got checked out, it involved an MRI for me to make sure I didn’t have a tumour (because of the relatively sudden hearing loss).
I’ve got both permanent tinnitus and hyperacusis too. Got it from a couple of really bad ear infections back when i was 19, I’m 31 now and it still sucks. What’s bad about it is that since the hyperacusis makes me really sensitive to louder noises, if i’m in a situation which is uncomfortable to my ears but fine for other peoples, it can make my tinnitus worse permanently. It completely sucks when that happens because the louder ringing is not easy to get used to at all. I just have to try and focus on other things, ride my bike, and just hope it won’t get intolerable.