welcome to hcm.
is a common entity.
done and you are post menopausal.
fistula and yeast(candidiasis
) infection might be the cause.
but those has been excluded.
so there are very few causes left.
no need to worry.
it might be due to senile vaginitis or bacterial vaginosis
these are easily amanable to treatment.
you may try evion cream inside vagina.
hope it will give comfort.
if not please depend on your gynacologist.
best of luck.