Is something wrong with my dog? [I Own a Dog]

I’ve been around dogs my whole life so I think I’m pretty good a picking up what’s wrong with dogs and their behavior.

I’ve gotten this dog a few months ago and he’s about 7 is what the vet said.

However I noticed he sleeps all day. (Unless we go to the park or outside) He growls a lot if/when you move him. Sometimes even when you just pet him.

I was thinking maybe a stomach problem, but he eats food just fine and hasn’t thrown up or anything.

Is he just not use to us by now? Or is it his age? (I doubt though cause I’ve had dogs up to 12 years old that don’t sleep around as much as he does.