Puppy screaming while defecating

[turbo]

Hello all,

Pretty new here so I guess I'll just explain my situation.
I have a 10 week old puppy (miniature dachshund) who has been very good at paper training. He usually defecates/eliminates on the newspaper in a designated spot no matter if we're there or he's left alone. He has a crate but we give him full run of the kitchen (puppy proofed).

He is always playful, energetic and wags his tail whenever someone enters the room, however for the past 2 days when he walks over to the newspaper area to defecate (poop) he will begin and then let out a loud yelp/scream while running and defecating at the same time.

We haven't fed him anything other than kibble and treats: puppy treats (Wellness) and the occasional peanut butter filled kong. (No chicken bones, people scraps, etc) He does defecate sometimes during the day without incident and the other day when taking him for a walk, he pooped out one of the strings on his chew toy (came with 3 strings, took other two, he ate one) but other than that, no toys were broken/damaged.

Not sure what is wrong (he doesn't butt shuffle or whimper when you pick him up) and I get a little worried. We also just had a vet visit for his shots approximately 6 days ago and everything was fine. He also has the occasional hiccup but as I'm a first time dog owner, I want to know if this is normal for puppies?

Thanks.