The diagnosis you are talking about must be vulvodynia
. Which is pain around the opening of your vagina with no identifiable cause.
From the elaborate visits to the gynecologist and number of investigations you have undergone, if no cause was found then this is most probably vulvodynia.
Unfortunately, treatment includes only techniques to relieve or reduce pain. Treatment options available are:
-Medications (eg. Tricyclic antidepressants, antihistamines-if itch is present, etc)
-Specific techniques that help you to reduce/cope with the pain
-As you have mentioned the presence of pain even while standing, you could request your doctor for injections resulting in a nerve
-Exercises yo strengthen the muscles of the pelvic region
-Surgery: Includes removal of skin and tissue of the region where pain is maximum
From the description provided, if you have undergone elaborate evaluation and not found a cause, then the diagnosis of vulvodynoa stays.
Hope this information helps. Feel free to write back to me for any further clarifications.