The result of a herpes zoster infection of the trigeminal nerve that was triggered by a severe sinus infection that backed up into my ear canal. At first I thought I had a severe tooth infection or something and visited my dentist. Ended up needing a bunch of work done anyway, but unfortunately, it didn't do anything for my nerve pain and may have even aggravated it a bit.
Horrible pain, isn't it? I've been helped by taking Valtrex for the herpes zoster and Topamax for the neuralgia. I also had to change the way I sleep, since it turns out I was grinding my teeth at night and making things even worse!
Try not to worry too much, it really doesn't mean you have MS or a tumor. It's not a rare condition at all, just do a Google search on it and you'll see what I'm talking about. I found plenty of information and support on the web and I'm proof that it actually can get much better. At this point, it only hurts me about once a day and I really don't notice it that much at all.
Here's a link to check out that has a lot of support info:
http://www.tna-support.org/Another one, since I think you're in Australia (if I remember correctly):
http://www.tnaaustralia.org.au/Good luck! Hope it gets better for you. Chronic pains sucks ass. :-(