If it's not a UTI, try switching lubes.
There are lubes for sensitive skins, that don't have a lot of the chemicals that can be irritating to us.
Here's a decent list. https://www.refinery29.com/en-us/best-lube-sensitive-skin
They are definitely more expensive than what you're using, but think of what you'll save in doctor's appointments. There are a ton of lists like this - google "lubes for sensitive skin" or "sensitive lubes".
You can also make your own lube from natural ingredients - http://teenhealthsource.com/blog/do-it-yourself-diy-lube/
If you are using condoms, make sure whatever you use isn't oil based.
To me, it DOES sound like a UTI. Just because it wasn't last time does not mean it isn't this time. Those are classic symptoms. I'd go get your urine tested.