My driver side headlight comes on and then blinks out after a few minutes but the passanger light works fine is it the bulb or somethings else

It is more than likely a wiring issue.

Simple Fix, complicated procedure... Your Head Light Blast is most likely done which means its time to replace a bulb. Its a D1S Bulb which is easy to find but replacing it is hard. Ive done it to my DTS and the process was first to drop the bumper to get the head light assembly off once its off its smooth sailing . SO my recommendation is if your gonna change the bulb, do all the bulbs in the head light including parking lights and turn signals