My Cat Doesn't Want To Leave His Crate

I've hadmy Sphynx for a while, and he is usually a sociable outgoing cat. I'm in college and sometimes when I'm going home I'll take him with. He doesn't like being in the crate, and meows almost the entire time. Sometimes if my boyfriend is driving me I'll have him out in a blanket and he doesn't mind that really. He seems to like my parents house, as there are other cats there for him to interact with and there's more space for him to run around, so I try to take him usually when I go. This last time when we got back to our apartment he seems to all of a sudden prefer to spend a lot of time in his crate. I thought this would only last for a few hours that night, because the next morning I lured him out and he was out socializing with me. I found out later after returning from class that he had returned and remained in the crate until I got home, he played a little and for the rest of the night has been in the crate. I lured him out again with treats and he almost immediately went back in. Apparently this has been the case a few times when I travel with him, according to my boyfriend, but I don't remember. Anyway, just looking for any information anyone can give me regarding this.

He might be sick or injured.

When was he last at the vets?

I agree that he might be hiding away because of a medical problem. If not, it might have to do something with security. If he’s been moved back and forth a lot recently but the crate is a constant he has probably begun to see it as his territory and something that remains the same no matter where he goes. Cats seek comfort in the familiar.