How can a warrant be issued if I was never contacted to know that I was charged in the first place?

I had an incident with another individual in October 2016. I got a piece of mail the other day from a law firm wanting to represent me for my disorderly conduct case. I thought it was interesting, so I looked up to see if I had charges. Lo and behold, I had a warrant for my arrest. I never received any kind of summons, or complaint, the police never came to my door. I did immediately hire an attorney to get the warrant set aside but I have to go with him and due to work, cannot go with him until a few days from now. I have had my other half driving me around-as I am now realizing if I were pulled over, I could have been taken to jail, with not even knowing I was charged.