I too agree - your cat is definately trying to tell you something, take him to the vet asap!! It sounds like bladder problems. If he can't pee, it's because crystals build up in his uninary tract and block the system. This can be fatal within a few days, the kidneys can get damaged. He will most likely be flushed through and get some antibiotic and you will have to feed him diet food.

Good luck with him!!

You can read more about this on other threads here - in the Cat health forum.