Up to a few hours after intercourse, I have a burning sensation. What is the reason for this?

Burning can have various causes - it can result from dryness, change in pH or persist after infection. What can be done at home is primarily to change underwear to one made of natural fabrics (cotton), sleep without underwear, avoid wearing insoles or use condoms, because pH titers in the vagina after infection, when in contact with another environment (e.g. semen) can cause some people an unpleasant burning sensation. However, the specific cause will help to determine the gynecologist. If the burning does not pass, it is worth talking about it with a gynecologist at the next visit. I leave a link that may be interesting: https://www.gdziepolek.pl/artykuly/infekcje-intymne-jak-sobie-poradzic