Two things come to mind. 1) is he possibly going to shed soon? (*Sorry it's late, I missed the part where you said he shed not too long ago.) How old is he? younger ones shed more frequently than the adulsts. Also, was it a complete shed? Maybe he's got some left that he's trying to get off?
2) how big is his enclosure? I've heard of snakes in enclosures too small, can cause then to be stressed & start rubbing.