I was thinking vaginal atrophy as well - perhaps better known as urogenital atrophy as low estrogen can affect All that area, including recurrent thrush due to embedded UTIs, bladder irritation/frequency, sore vulva/vagina with little cuts and sores, skin splitting etc.
The skin membrane becoming thinner can affect all this area - vagina, vulva, urethra and anus. Things get sore, and we can get more adverse reactions to creams etc.
If this is the case for you, then local estrogen can help. Vagifem can be used internally (a tiny blue tablet inserted twice a week after the initial 2 week loading dose), and/or cream that can be used both internally and externally.
Natural things that can help soothe - YES products, water based and oil based, Olive & Bee, which is an olive oil and beeswax mix, and various others. Beware of lube with additives like parBens and glycerin- I started to have thrush like discharge to a Superdrug one.
If you get no joy from your GP in finding the cause, getting seen at a GUM clinic might help - they’re not just for STIs but can do general MOTs