His nails could be the culprit....need a trim, pronto!
Yep, just came here to say that your dog's nails need a massive trim. Probably will take you a few weeks to get them down to the appropriate length.
This site shows the proper angle to trim nails
Cutting Your Dog's Nails . . . How Important Is it Really? | Susan Garrett's Dog Training Blog
It has a good talk that is unfortunately not captioned, but watch it for the drawing the vet makes at about 5:10. What she is showing is first the traditional cut that people normally make. Then she shows the angle that people should be making, and talks about how that extra bit under the quick goes away very quickly just by the dog's normal walking. The angle that she recommends works to push the quick back much better than the other angle.
This site explains a bit of what the vet explains, just with words and pictures!
The Truth About Nails | NE Ohio Greyhound Rescue, Inc. It shows how with just a little extra length on your dog's toes you completely change how the dog stands, and it goes from standing on their toes to rocking back on their heels, and this stretches out their ligaments and causes a cascade of pain and injuries and it's actually a big cause of obesity in dogs. The only issue with this site is it shows the old way to trim nails, when you should trim them like in the first article. That's how I trim my dogs' nails and have for years.
You're supposed to get the dog's nails trimmed to a length where you can't hear them when they walk on a hard surface like wood floors or bathroom floors. That does not help me any! I aim to keep mine trimmed as short as the paws in the dog legs photo at the top of the first site. The photos go through a series, just watch until you see a bunch of dog legs with super short nails. Those nails are for dogs that are in competition (like agility) but if you make that your goal, your dog's nail length will be fine and your air bed will be fine too.