What Causes Pain During Urination After Having Unsafe Sex?

Hi I had sex back in December un protected. I have been having protected sex with the a different person and only that person since January. I woke up this morning with pain while I urinate. It has gotten a little better throughout the day and sometimes it doesn t even hurt at all. Could I have possibly gotten an STI from the person back in December and it is just showing now or is it highly unlikely? I don t feel sick or anything just the problem when I urinate. I had a Pap smear after I had sex with the person in December. It was only a few days after.