When I plug in the wire (which goes to my outside sump pump), the
circuit breaker trips. Also on the circuit are a few of my living room
lights but they always seem okay.

I bought the house about 2 years ago and at first didn't even mess with
the outside wiring. The low voltage lights were working half ass and
the sump pump kinda just did its own thing (work sometimes, it's not
essential because it is like a back up). I finally dived into the
project and was plugging things in and out to try to figure out what
goes where. Now, every time I plug that sump pump wire in, the circuit
breaks.

I guess my question is, should I try anything else or should I just
figure this is a time I need an electrician?

The pump is not essential, but it is there. So I have standing water
and its getting near mosquito season.