My little man was the same when I brought him home. He didn't do it to bug me, his breeder used puppy pads to train him so he thought he was supposed to potty inside.
I wouldn't bring in the pup until he goes potty outside. With Acheron, I make sure he pees 2-3 times and poops once before I bring him inside.
Mom To~ Dakoda (b/t GSD), Acheron (black GSD)