What Causes Headache And Flickering Lights In Vision?

this probably sounds silly but, when i was driving today, i continously saw flickering lights and all of a sudden i saw a bright light and it sent a wave of pain through my head.. and it was definately not lightening or a light, do you think it is just "in my head", or could this be a sign of something with my vision or anything, im not extremely concerned about it, but it was sort of unusual so i wanted someones opinion on it