I was reattaching a dome light fixture to the ceiling and when the plate on the fixture touched the screws it was to attach to, there was a loud buzzing and the circuit tripped. Is this because I was stupid & didn't turn off the breaker before trying to reattach it or is there a bigger problem I should call someone about?

You can run into this situation if you had a switch loop circuit since the ceiling power feed would still be hot even if you turned the wall switch off. That's why you test all the wires to make sure there is no power.

U should never work on electric with power on. U are lucky u didn't get zapped.

Chuck

There should be three wires. A 2 for the light and one for grounding. Sounds like it's not grounded properly. There should be a screw on the plate for a grounding wire. I would suggest an electrician.