Ohhh, that limp does look quite a bit worse and he's so sweet that I just want to hug him.
I agree with Denise, something looks kind of odd about how he is holding that sore leg, too. I also noticed in the video that his paw seems curled and when he was giving you the paw, his bad leg was curving toward his left, as opposed to giving you a straight paw. He may be clenching his toes due to pain. That is one of the ways that we watched Halley for pain (I'd forgotten this until now) was that she'd "cup" her paw, but the curve to the leg is puzzling. I'm sure that he is must be more sore today from the vet exam (as well as the walking in & out of the vet, car ride, etc.) but still, that limp looks so much worse than the early videos that I saw. Also, the way that his leg is curving is so different than how Halley held her leg with a tumor in the proximal humerous (just slightly below the shoulder joint). She held her leg up, but it was straight, not curved. I don't know anything about spinal problems in dogs, what Denise said does sound really intriquing and I'm sure that a ortho vet could look at that, too.
Stick to your guns, Kristina! I know that no one wants to think that he's getting worse (just "not improving" does sound better
) but it sure looks a lot worse to me, too and you have the videos to document the change. I would definitely get him to a specialist ASAP. That fact that yesterday's vet doesn't know that a Pyr almost literally *won't* show pain by crying, etc. makes me concerned, too. If he/she is waiting for Yukon to cry to recognise that he's in pain, then he's going to put that sweet boy through a lot of unnecessary suffering.
I wonder if the ortho vet would find the series of UTube videos enlightening, too. Often they just see the dogs walking for a short distance in the office. So it might be helpful for him/her to see the progression of the limp over time and how he has been walking and moving his right leg (giving you the paw), etc. when in his home environment.