1998 chevy pickup, passanger side brake and turn signal will not work, all other lights work.

There's a switch on the brake pedal arm that controls the brake stop lights, that needs adjustment or replacement.
Hope this helps.

First thing check all fuses, if ok your problem more likely rear tail lens circuit board where your bulbs push into. the sockets over heat and melt . this is a problem with these trucks from 1988 to 1999