I'm sorry to hear about your troubles, Brian. I've had ringing in my ear for many years now, which used to be somewhat intense. I eventually got used to it to the point where I hardly notice it unless I concentrate on the sound...but it sounds like you're experiencing that on a whole other level, at least for now. While I'm not as an experienced meditator as many of the people on this board are, I was would guess that you're going through an especially intense part of the Dark Night in the Stages of Insight or something leading up to that.
If you're not familiar with the progress of insight in the vipassana tradition, check out
this link which will bring you to the Dark Night stages, but maybe read through the introduction to that section as well.
It would be helpful to people on the board if you can describe your meditation experiences on the retreat. Any major events come up during your meditation? Bright lights, intense vibrations, etc?
Anyway, as it's meditation related I think it's pretty certain that it will pass. When you start doing meditation on an intense level, there are many changes that occur in the brain and sometimes they're not altogether pleasant...but I think in the end it means progress towards insight which also means the issue will eventually subside (or at the very least, your anxiousness and suffering about it will). For instance, right now I've got an intense pressure that moves around in my sinuses to the roof of my mouth and nose that shows up every time I start to gain some concentration. While I'm curious about it and you may see a post about it pop up at some point, all the advice I've been given is not to worry and just keep practicing as one can. And in my last sit I just focused on it for most of the hour and at one point it began to "open up" and loosen some, although it still is hanging around. So these things do change.
So fear not, all is impermanent, though I imagine it's hard to gain any comfort from that right now. But if you've made it this far, hang in there a bit longer and it should pass.
In terms of advice about what to do, it generally boils down to sitting with whatever ails you and staring it straight down, at the very least trying to see its impermanence, in order to gain insight. I'm going to hold off on making any solid recommendation given my lack of depth of knowledge about this territory, so hopefully some of the more experienced meditators will chime in.
So anyway, just my take on your situation given the information you provided and my limited knowledge and experience in meditation. Once more it will really help if you can supply more information about your experience with the Goenka retreat and your experience with meditation in general.
I wish you the best of luck and that you find relief soon...which I think you will.
Best,
Chris (formerly of the "C K" account...accidentally locked myself out of it, but I wanted to reply to this post sooner rather than later, so I created another account)