Swimkris, my husband mentioned it might be fleas, and no we don't have him on a regular flea medication or treatment.
Fyreflie, I've not seen him nibbling or biting at all. I did see him scratch his neck once today, which I've never noticed before either. Otherwise it's just the hard licking and he's licking different places. Sometimes it's just his down the front legs and chest, other times it's his back and other times it's his back legs, and then running like he's being chased by something.