There are two reasons your pork may not be easy to shred. 1. It wasn't cooked long enough. Make sure the internal temperature is at least 190 degrees Farenheight. At that temperature, the connective tissue that holds the roast together begins breaking it down making the roast easier to shred. 2. You accidentally bought a leaner cut of meat like pork tenderloin that was not meant for longer cooking and has dried out.