Pain after immunization shot

[moontamara]

Casey just got his second immunization shots about twenty minutes ago (3month puppy) and the vet told me it would hurt, but I'm not sure if the way he is acting is normal or not. Whenever he tries to walk somewhere he pushes his behind down (kind of like when they are trying to wipe themselves on the carpet). He had his last bowel movement not that long ago so I don't think it's related to that. He's also very restless, like he's trying to get away from the pain, moving from place to place and then lying down. Should I take him back to the vet? Pls answer quickly if possible.