I had this. It was bloody horrendous and wiped out a couple of years of my life. I was able to work but my social life died, I was in constant pain and sex, tampons, sitting were agony. I saw a private gynae who put me on a long term course of antibiotics (a fairly full on course of ciprofloxacin and metronidazole for a month followed by a prophylactic dose of nitrofurantoin). I was on antibiotics for several years, and also used dermovate when I had burning pain (I had intense intermittent UTI type-pain and lower grade constant burning in my vulva). The pain gradually improved and I am now pain free (and was able to have two babies vaginally, which I never thought I'd be able to do). This is not the normal course of treatment for vulvodynia (I never tested positive for bacteria so it's counter intuitive), but it did work for me. Some other things that helped a lot were:
Coming off the pill (ALL hormonal contraceptives made the pain worse for me).
Stopping wearing trousers, especially jeans. Cutting the crotch out of my tights (sounds weird, but they made me really sore!)
Making sure my vulva never came into contact with soap or shampoo
Wearing only 100% cotton underwear (from m&s) and washing it at 60 with only a smidgen of detergent
Avoiding drinking too much tea, coffee or alcohol and drinking masses of water to dilute my urine.
No-one really knows the causes of vulvodynia and I often wonder if it's really several different conditions lumped under one term. This means that different treatments work for different people, so you may have to try a few. Have you looked at the vulval pain society website? They also run a support group if you're near London.
Good luck, I know how hard it is to be in constant pain and have to hide it from everyone. You have my deepest sympathies.