It is kind of hard to describe how they should feel... It's usually pretty easy to tell if they have a hard spot. Even after a big meal they can temporarily have a bulge on their side (not an impaction, just a really full belly!) Can we get a few details such as temp and humidity (these effect digestion), what his diet consists of, and how often you feed it?

Also, Pacmans tend to poop in their hole then relocate to a new spot, stay there until they poop again, repeat process. So even if you haven't spotted his little presents, they might be there. Does he change burrow spots often?