fiend

In the last few weeks my staffy pup has been going along furniture with his body, and it seems to be getting worse. I have checked him and he is free of fleas. Is there something wrong or is he just pretending to be a cat ? Also, hes has a lump in the middle of his neck that looks and feels a bit like a really extruded scar. It's about the size of a sultana. I'll be taking him to the vet soon for a few other things, i'm just wondering what you guys think thaaaaaaaaaaanks!