C.V.
Please don't give your child an electronic device to soothe him. And unless you want him sleeping in your bed permanently, leave him in his own bed. That might be the reason he keeps waking up...he knows if he makes noise and whines enough times, he'll get his nook or will get to come sleep with you. Stop giving him a payoff.
He may be getting some molars in. A snuggle, some children's Tylenol, and leaving the room quiet and dark is enough.