Thank you for sharing your story!
I found it very interesting that you said that amoxicillin took the pain away. You might of had Aerobic Vaginitis, specifically Group B Strep since it is often treated with amox/penicillins. A lot of doctors don't know about this cause of vaginitis and it won't come up on a general vaginal swab unless the doctor specifically orders to look for it. Here is some more information on Aerobic Vaginitis for anyone who thinks they may have this:
There is a hypothesis that aerobic vaginitis is caused by hormonal imbalance (specifically loss of estrogen leading to a vaginal ph that is high and harbors bacteria) which might also be why the dong quai helped.
I had aerobic vaginitis and my estrogen levels were also very low. I am underweight (which leads to estrogen loss) so to prevent it from coming back I'm trying to healthily gain weight. I'm also taking hormone balancing herbs (dong quai and vitex) to help get my hormones back on track!
I think that anyone suffering from vulvodynia should get tested for Aerobic Vaginitis or Group B Strep. It may not be the answer for everyone, but it's definitely worth a shot!