I started sleeping on my stomach for about a month, and one day my tinnitus got way way worse.. It was distracting me from work. I evaluated what I may have changed (diet, exercise, sleep). Eventually noticed my change in sleep habits, and switched back to sleeping on my back (with the help of Benadryl). Needless to say, the severe tinnitus subsided.

I have to imagine there are more things I can do with my posture / neck to further eliminate my tinnitus.