Why does my six month old cat keep peeing on my bed?

I just got my cat Inky from a rescue shelter at my local petsmart they said that he was litter box trained, when we got him home he would use the litter box at first but now it seems that he has almost completely stopped using the litter box and started using my house and especially my room as one huge litter box. My main question is, is he doing this becuase he is not neutered yet or what I really need an answer on this I'm getting tired of waking up in a pool of his pee.

Perhaps the litter you're using isn't to his liking. I'd look into changing it to a different type if that were me. If not, please seek advice from a vet as there may be something wrong.

quite often this means that there is something is wrong. Sometimes when they are ill (say with a UTI) they associate the litter with the pain. It would be a good thing to get your vet to have a look at him ASAP.

Are you sure he is not neutered?? Petsmart and such dont usually adopt out 6 month old cats that arent fixed.