Shouting at Pup
Yelling usually goes hand in hand with repeating commands. Again, Pup's lack of response is not because he didn't hear you…assuming you've trained him on the required command. It is, rather, because he doesn't feel like responding. If the cause is lack of training, back up and do the training.
Otherwise it is a dominance issue and should be corrected now with a mild rebuke rather than waiting until you've firmly trained in the trait of only responding when yelled at. Then it takes a more severe correction.
On a more basic level, shouting only makes it harder for Pup to respond. Shouting usually either excites Pup, or makes him afraid. Neither emotional state makes it easier for Pup to do what you want.
If a 6½-foot NFL linebacker was standing in your back yard yelling at you-"You better come over here to me, you blankety blank"-would you go to him? Not if you have half a brain. This is approximately the same picture you give your dog when you stand there yelling at him to try and make him come to you. The major difference is that he doesn't understand the words. If your dog is intelligent, he's not going to come to you in that situation.
Do yourself and your dog a favor that will make both your lives more pleasant. Don't shout.
Pleading When He's Out of Reach
Changing to a pleading tone of voice seems to be another universal human trait triggered by dogs. When the dog gets far enough away that we think he's beyond our control, we revert to an asking tone of voice. You know the one. It has a question mark on the end of the vocalization. If a dog could speak English, you might as well be saying: "Don't obey me. You are beyond my control." Dogs don't speak English. They speak in the language of tones and mannerisms and body language. They understand very well what that question mark on the end of a vocalization means. That tone signals "don't obey."
Here is where consistency is key in dog training. Always project yourself as if you are in total control. Act the same and use the same tones and mannerisms whether your dog is next to you on a leash or 200 yards away.