Hi
Sounds as though you need some local oestrogen. It's probably vaginal atrophy - it often effects whole area and the bladder as well. I wouldn't use talc, even stuff that is supposed to be for intimate areas. If the top of your thighs are sore then an unscented moisturiser like E45 would be best. Vaginal lubricants can also give relief for the vagina. Needless to say you need to avoid tight clothing etc.
DG x