Brake makes a dragging noise

Hello, i have a 2000 Ford Taurus, the back brakes are drums. they have been making a dragging sound and today something popped and the brake got real tight and now makes a louder dragging sound. What could it possibly be and is this an expensive fix???

Brakes have a part that makes a squeaking or dragging noise to let you know they need replaced, it is this or they are dragging. Either way you need to take off back wheels and have them checked.
If you drive it 1-2 miles while it is making this noise stop and carefully feel to see if rims are hot, if so they are dragging.