Maybe I'm interpreting this quote differently than the rest of responders so far.

When you make above statement, are you talking about the green turn signal indicator on your instrument cluster in the dash?

If those are the lights that are staying on, and you also say all your turn signals and brake lights are still working properly,then I'd be looking at the ground for the cluster up under the dash, and not so much in the trunk...regardless of this being the area that was recently worked on.

If all your signals/brakes/taillights are working properly at the back of the car, then I believe you don't have any wiring or ground problems back there...