Random yelping, is it normal?

by R.C.
(SE, MI)

Hello everyone. I have a 3 mo old boy and have had him for a month. He's fantastic, smart and loyal. The only thing I'm concerned about is his random yelping. He's been doing it on/off since I’ve had him and finally think to ask some experts (my vet said at beginning some do that when sleeping hard). Anyway, when he was first home he'd eat super fast, bloat and when we'd pick him he'd yelp. Figured this to be gas pressure and fixed the eating situation and this has stopped.

He yelps, just once, not a bark, just walking around, sleeping, waking up, etc. It sounds like he's hurt but it doesn't affect him; he keeps on whatever he's doing without jumping or being spooked. It’s always so unexpected.

I've tried to recreate it and can't. I can touch him all over w/o a yelp. He doesn't try to get at his ears, doesn't do butt races on the floor, nothing. He's active, eats fine, sleeps normal, plays. A friend has his brother and we get them together at least once a week for puppy play time and they romp around fine. Last night they played and he yelped more than ever before when it was time to go to bed. He’d yelp adjusting himself, or when we’d move him, or wake him up. This morning, only yelped once but has been stretching far more than normal.

I’m hoping someone can share an experience to let me know I’m just being paranoid (I’ve never owned a puppy, I’ve always rescued and fixed older dogs-lol). I hope its strained muscles from playing too hard, new experiences and it’ll be okay. Or if it is something more serious like ear infection (which doesn’t look like it), or bad bones, etc; Any guidance would be greatly appreciated! Thank you!