I’m so confused. My vagina hurts like a mf. Especially when I walk or move around.

I couldn’t sleep or move that’s how bad it was so I went to the ER. They ruled out any STDs (I have a regular partner, my fiancé) and no UTIs. Said it looks normal too. Prescribed some antibiotics and topical lidocaine. I refused stronger painkillers since they wanted to give me codeine. I’m so confused??? What is it and why?

Just some context: I’m breastfeeding my 8 month old and before the pain started I spent the whole day sitting down behind the computer - working from home. My fiancé and I had sex yesterday afternoon and I always make sure to pee and clean after.