4-8 yr old male cat, bloated and won't use litter

My baby kitty, a black tomcat named Hugo, is between 4-8 (he's a shelter kitty and we keep getting conflicting answers on his age). He is neutered and has tons of Ph and bladder problems but we regulate it with his diet.

Recently, hes been meowing a lot and begging to go outside (all our kitties are indoors but he likes to sneak out), plus his stomach is bloated and kind of hard. He meows or protests when I touch him and pick him up.
He doesn't have any problem sleeping or eating or drinking water and I'm really worried.
I'm going to take him to a vet hopefully soon. Please help me, and sorry if I broke a rule or anything I literally made a account to ask this question. Thank you.

Welcome to The Cat Site,

Hmm...it sounds like your boy might have a bladder infection/urinary tract crystals? My boy has a HUGE history of them. Does he use the litter box? What size is his urine? (I know weird question but...) Has he been dewormed?

If he's not going to the bathroom, either urinating or pooping, he's got a serious problem which needs medical attention NOW, not later.  You probably already know the issues associated with urinary blockages, but he could also have a bowel blockage, which could also be fatal.   I'm not saying it's either of these, because it's impossible to diagnose over the internet not knowing his history and us not being Vets, but it's obvious to you that something is wrong, so please try to get him to be seen.

Is there some reason you haven't taken him in already.  If it's money, maybe this article will help:  http://www.thecatsite.com/a/no-money-for-vet-care-how-to-find-help-and-save-your-cats-life