My dog, Oreo, is having a LOT of pain when he poops. We took him to the Vet yesterday. He had to stay overnight. They gave him an enema, etc. They said his system is Ok, but he may have a few cracked vertebrae in his tailbone. He holds his tail straight down, and yelps in pain when he lifts his tail, or if the vet tried to lift it. What would cause this? They didn't take x-rays or anything, but suspect that's what's going on. Is there anything else that could be wrong? We feel so bad for him, because he just cries out in pain. They gave us pain medication to give to him for now. Is there anything else we should be looking in to?