Has anyone else had this problem?

Bertie,my pekingese, aged 3 , suddenly had a bad pain on Tuesday morning. I took him to the vet (by which time the pain had gone) but his temperature was raised. Close inspection revealed nothing else. He has had anti-biotics, pain killer and anti inflam. drugs. Now the temp is down, he is full of beans, and eating. Except,each morning the pain comes again and causes such screaming for about five minutes. He does not seem to be constipated and urinates O.K. Tomorrow he is going to have some X.rays on spine and intestines. Has anyone else had anything similar with their dogs?

All advice would be much appreciated. Thankyou,

Bertie's Mum.