2008 Ford Focus • 30,000 miles

This morning I started my car and tried to pull of but my rear brakes were locked asif I had left my handbrake on I kept rocking the car back and forth a eventually there was a crack and the car was free and pulled off just like normal, later that day it did the same again handbrake off but brakes still on what could be causeing this problem and is it serious its only just hit 30000 miles so surely I cant need new rear brakes ive had alot of work done on the exterior of the house which involved a lot of dust and ever since this has happened could it be linked or just coincidence
November 9, 2013.

It's proably a coincidence but pull your back brakes off and check them

Nov 9, 2013.