Agree with Karla. This could be pain related and evidently recent behavior.could be something has made him nervous. Hard to tell without actually seeing what is going on.
A few basics - is he eating and drinking normally?
Any change in his stools?
Is he scooting his rear around, turning toward it, etc? Anal glands that need to be expressed can cause some really odd behavior. Check around the. Anal area fir any swelling or irritation.
On to possible pain issues - give your dog a good going over. Check inside the mouth, the ears. Slowly move the head from side to side and up and down to see if there us any resistance or pain. Lift front and back legs, slowly to see if there is any reaction. Gently run your fingers, applying a little pressure along the spine down to the tail. Check the pads of his feet and in between the toes.
Check his belly for any tender areas, lumps, etc.
If you hit a tender spot, he will most likely let you know. Sometimes, you might feel them quiver when a sensitive area is touched.
Checking our animals regularly should at least be a weekly routine so you are familiar with the dog and may catch something amiss.
If this continues or if other symptoms present themselves, a Vet exam might be in order.
Yes, do let us know.
It sounds "PAIN" oriented to me.....Have you checked both front paws thoroughly? Does it appear he can't use his front legs or doesn't want to? If so, that could be a herniated disk in his neck. Extremely painful!!!!
I personally, would get him to the Vet ASAP.......Good luck and let us know about him....Karla