In reply to Trevers:
> Mine does go away. I've got a really deep filling on one of my teeth at the back, and it's very close to the nerve. Every so often I get bouts of pain for a couple of days where it's pressing into the nerve, but then I go for months at a time without feeling a thing. So the pain isn't alerting me to anything wrong, it's just pain for the sake of it.
It's not your 'filling pressing into the nerve', it's pulpitis. Right now it's reversible pulpitis but one of these times it won't resolve and if you're lucky the tooth will just die. Then again it might blow up into an agonising periapical abscess (if you think the pain has been bad up to now you are in for a surprise) or perhaps just lead to months of chronic inflammation.
> I can get a root canal but if I can deal with the occasional bouts of pain I don't really need to.
Or you could talk to a dentist, who may have other options. Make sure you have his number ready anyway, because you'll be needing it in a hurry at some point.