electrical problem (brake lights do not turn off)

[cardboardbox]

s13 coupe, sr20 swap.

I was working on my exhaust/turbo system unbolting pipes and touching this and that. When I was done I noticed that my brakes lights refuse to turn off (unless I unplug the battery). I took it for a spin and also noticed that when I apply the brakes the floor lights flicker on and off sometimes. I'm not sure where to start when it comes to electrical systems other than the fuse box and battery. Any techincal support is appreciated.