I work for this trucking company and I drop off a load and didn't get paid
If you're an employee, your company should pay you. If you get paid by the job, you might send a demand communication (email, mail) to whomever is supposed to pay you. Keep a copy. Then, if you still don't get paid within a reasonable time, you might have to file a lawsuit either in small claims or civil court, depending on the dollar amount. Don't wait too long, though.