If I have a signed payment agreement can I get a judgement without going to court?

You can't get a judgment without the court being involved.  You could get a default judgment, and because it is based on a written instrument, etc., you could get a default judgment in District without going to court, if the defendant defaults and fails to answer or otherwise respond to the summons and complaint.  If the signed agreement had a confession of judgment, you could also probably avoid going to court, but you will still be using the court.