Has this just started, because this is usually an indication of being in pain and may have injured itself. Check and see if certain are is tender. If she continues, she may have broken something and must get attention from vet
My Dogs Been Yelping In Pain What Should I Do?
My dog yelps in pain...sometimes only in the morning. This started as a pup, now she is about 1/2 way thru her heat cycle and has been in pain all day? Any ideas?