I had one diagnosed about 15 years ago, in my early 20s, and subsequently had surgery to remove it. It was bad enough that I couldn't run, and it hurt to walk after more than a short walk (very annoying pain - it's a growth on a nerve, so it's like toothache, or the 'jarring' pain you get after stepping heavily onto one foot).
I was wondering whether to live with it, or have surgery - so they did a nerve block, where they inject anaesthetic into the affected nerve. It's only a temporary painkiller, but gave me a pain free 24 hours or so, which was a relief, and so I went for the surgery. (I'd been limping for a while, and this was starting to give me back and hip problems, was another reason to have surgery).
Very quick op, done under local, but it does take a while to recover. I couldn't walk on the foot at all for a few days, and it took a while before I could walk normally. The nerve gets bruised and tugged around, so I had a lot of numbness and odd sensation in my foot for a few months afterwards (I wish they'd warned me about that a bit more, as it was a bit alarming, but there we go!).
Now I have numbness between 2 of my middle toes, and in a small patch on the ball of my foot (and a small scar on the top of my foot). But I have no pain, and the numbness doesn't bother me.
Re non surgery - the insoles that help are one that encourage your feet to 'spread'. If you wear tight shoes, or socks, you squeeze your metatarsal bones together, and this squishes the nerves between them. Which is bad, as HippyGalore says. If you put something like a squash ball underneath your foot and gently press your foot down on it, you can feel how you're opening up the space between your metatarsals. Special insoles which have a mild 'bump' pushing the middle of your foot up a little can help a lot, by reducing the 'pinching' that aggravates the neuroma.
(Celebrity sufferers include Wales rugby captain Ryan Jones, who's got such big feet, he has to have boots specially made for him... www.walesonline.co.uk/news/wales-news/2009/06/08/how-ace-put-the-spring-back-into-ryan-s-step-91466- 23811427/)