Dear madam i can understand your concern.
in my opinion there might be a kind of injury
during intercourse which are quite natural some times.
some times this small injuries may heal spontaneously but very rarely they may get infected but reasons are numerous....like stress
and bacterial contamination from perineum
there may be super added urinary tract infection
kindly meet a gynecologist and consider taking antibiotics .
drink plenty of water
Hope this satisfies your query.
Thanks for using HCM.
Feel free to ask any more questions that you may have.
Consultant Obstetrician and Gynecologist