turn signals blinkers

This just started last night. My blinkers are only working on my right side. Could this be caused by anything other then a bad turn signal switch?

Hey guys, by law the state of massachusetts requires me to have blinkers on my bike. i need to find the SMALLEST ones possible (just to shut johnny law up). i have seen in the past those "polka dot" signals and i can't find them anywhere! anyone know where i can find em!????!?! thanks!