Center brake light works but both the left and right brake lights do not

Yes the turn lights work just fine. They are a separate light above the brake lights.

When I look at the bulbs the ones that should light up look like the same ones that light up for the brake lights. Do they have two different filaments in them? One for tail lights and one for brake lights?

Actually on my car there was one bulb with two filaments in it. The filament for the taillights worked great but the one for the brakes didn't. I used an O-meter and there was power to the brakes when the pedal was pressed. I went to the auto parts store and bought two lights for $5 bucks and now they work. I find it strange that both lights went out at the same time :)