brakes split

about for months ago i replaced my front braske pads and rear brake shoes, also i replaced my rear drums . the pads on the rear wre cracked . well, four months later my rear pads have completely split AGAIN. what could be cuaseing this. im thinkin maybe a bad spring but not sure. on occassions the truck did feel like the rear brakes were grabbing when i would start the truck up and go forward. could the emergency brake cause this. any help would be appreciated