blinker light goes solid when brakes are applied

my driverside blinker stops flashing when I apply the brakes. Even when my blinkers aren't turned on and I apply the brakes the lights goes solid. My front drivers side parking light is also out but i can't see why this would be the cause. all blinkers work fine without the brake pedal depressed. so I don't think bulbs, fuses or flasher switch, are the issue. Please help me I am tired of using my hand to signal a left hand turn, especially in my new truck.