1989 Chevy Beretta Brake Lights/Turn Signals

I have no brake lights except the 3rd one in the rear window. I used to have them except on the drivers side usually when I had headlights on or using the left turn signal. My turn signal also doesnt work I have to pull it back in order for them to flash. The right side sometimes works. But left you always need to pull the lever in order for them to work.