What is the process in filing for child support/custody?

Here's my situation summarized..I had my son last October with my ex fiance however now things aren't working out and he's kind of crazy so I know for a fact that if I wanted to handle this out of courts it wouldn't happen. He refuses to accept that it's really over. I moved out of state with my son bc I went active duty (I was in the Army reserves before). I did this to make a better life for my son and bc his dad was bs'ing as in smoking weed..working dead end jobs not saving any money and living at home with his mama still. Anyways, I never changed my home address with the DMV when I moved, my drivers lisence say that I still live in VA while I am really residing in PA. My sons dad however lives in VA still. Can I just go to the county courthouse here and file for child support? Also, do I need to file for custody too? Also, do I have to pay a lawyer for this? Save the lectures people I just need some advice/guidance. Thanks in advance!