Std, uti, or something else

Patient: I am a male 18 years old and I recently had unprotected sex with one of my ex girlfriends. I came home and a few days ago I had a slight pain when I peed. Its not extremely pain just slight and afterwards there was a slight itchy sensation in my urethra as well. This went on for a few days but the pain and itch are gone now. I did reseach and om not sure if this is a uti chlamydia or something else.

Symptoms: Slight pain in urethra when peeing and itch afterwards. Both have gone away