Wow, I wasn't aware of this thread. I literally have a (head) MRI w/ contrast next week related to tinnitus (and some vertigo) to rule out anything "bad" but not expecting anything to come out of it (have had CTs come back clean). I also have pulsating noise (C# ish around 8.7Khz), a really high pitch A# squeal (~14.91KHz) plus some lower volume "feedback" about a semitone lower (A, which creates some uncomfortable dissonance), but only in my left ear. Like the intro to Flying in a Blue Dream from Joe Satriani but waaaay less musical.
I use an app called "Relief" when it gets pretty bad to get some sleep, since not sleeping definitely makes it worse. Will read through the thread for other tips.