1994 Chevrolet Truck brake sticking.

With no other details or observations, your best bet is to have the brake system inspected by your mechanic. The rear shoes could be worn down to the metal frames and are grinding on the drums. A parking brake cable could be stuck in the partially-applied position. That will make that brake grab too hard under light brake pedal pressure. In severe cases, grooves can wear into the backing plates, and the shoes catch on them. That can delay that brake's application or it can cause it to not release freely.