@mmoss: I have found vaginal burning for me to be one of two things.
(1) general irritation/dryness … I’ve been told “use dove soap or no soap” when washing the area. Also be sure that you get all the soap off. Do use some kind of moisturizer after … my favorite it’s just a pat on a light layer of Vaseline. You may need to rinse after peeing and reapply until you’re healed. Sometimes even the urine can irritate the area when you have a flareup.
(2) Fissures: have you looked at the area to see if there are tiny cuts/tears in the skin. They can really really sting! The only way I have been able to get the cuts to heal is to use a topical antibiotic called Mupiricin (I believe the generic is Bactroban). You will need a prescription for this.

Hope this helps!!! Good luck.