When you light up a nerve pretty good, it'll hurt for a day or two. Once the pain goes away, just stay off of it as best you can. If it's causing you pain anytime you eat, then you'll need to find a way to get it taken care of. It probably only bothers you if you get it real good with something hard, and that you can avoid reasonably well.
The long term solution will be to get it crowned. Alas, that's expensive as hell. The good news is that it has to be done in 3 steps, and depending on how your dentist operates from the billing standpoint, that might work well for you. The fist step is a temporary crown, which should actually solve your problem and is actually reasonably durable. You can probably get by for a year easily on a temp. If your dentist only charges after the entire thing is complete, you could conceivably get a temp put on and then just never go back. They might charge in thirds for each step, in which case it would only cost you about 3 bills. If he insists on the entire amount up front, then find another dentist. Either way, I'd be looking for a way to at least get the temp put on.
Being scared to eat anything because of possibility of severe pain with every chew is a really shitty way to go through life.
I had a similar issue with a tooth that had recently been filled (after a cavity). Every time I'd bite into anything, it'd hurt like shit. I eventually went back to the dentist, and he couldn't find anything wrong with it. He repeatedly jabbed it with sharp things to get a response, and I didn't feel anything. He attributed it to sensitivity, so I went out and bought some Sensodyne, and now it feels perfectly normal.
I had a similar issue a while back and the culprit was actually the tooth above it. Grinding down the teensiest bit of the upper caused it to stop putting so much pressure on the lower, which alleviated 90% of my problem.