Somethings up with my cat

Question
I have 5 cats. The one I am concerned about is 8 years old, male. My cats eat dry food only and have access to it all the time. This cat, his name is "Greenlee" has been staying in the exact same spot in the back bedroom for days. He doesn't come out on his own that I know of. I don't think he is eating. He seems to be favoring his front paws, however isnt bothered when I touch them in anyway. If I get him up, he tries to sit not allowing pressure on those front paws, he does not want to walk but if he has to, he favors those paws. I don't know what to think. I have felt and squeezed all around the paws, arms and shoulders. Everything feels fine and I get no adverse reaction from him. It doesn't make any sense. I do not know if he gets up at night to eat or use the box. But he certainly doesnt through the day.
Any ideas?

Answer
Time to take Greenlee to the vets. Something is really wrong and it might not be what you think. He could have some swollen lymph glands up around his neck that make walking painful, he could have some bites festering in his paws.

It's only a guessing game from online but I can tell you this, he needs to start eating and drinking or he is going to get a lot sicker really fast. Cats don't do well not eating after 3 days.

It is not normal for a cat to isolate itself for days and they only do this when sick.

He needs to see a vet and soon!