Strange behavior?

I found my kitten by a DQ one day, around the beginning of June this year. He was about three weeks old then, and my boyfriend and I raised him. He has been very loved and spoiled, and when we first got him he would beg to be cuddled and petted, and hated sleeping alone. He was almost constantly purring, and he was extremely friendly with people and was always just a huge lovebug. As of the past month or so, however, he has become increasingly aloof as far as affection goes. He might rub up against your leg to say hi, but then he scampers off if you try to pick him up. He used to just like to lay purring in your arms whenever he came to say hi. He still follows you around sometimes, and comes to you for playing, but he doesn't even seem to enjoy petting or cuddling anymore- or even attention in general. He never purrs, no matter HOW you pet him or cuddle him or love on him, and he always is struggling to try and get away. If you want him to lay with you, he pulls away and runs off, just to lay down a few feet away and sleep over there.

I understand that some cats, if raised a certain way, may become very aloof... But he was very physically affectionate before, and we have always loved all over him his whole life. He has spent almost all of his young life in semi-constant human contact. He has a very funny, almost canine personality for the most part, except for this sudden dislike of any physical attention. If you try and pet him, he usually runs away. He does love a good game of fetch, though. Haha.

I was wondering if there may be any specific reason for this? Perhaps he might become more affectionate after he is neutered? He's still just a baby, so I'm also kind of confused as to the reasoning for his aloofness. Is there any way to make him sit still long enough to see that petting and loving is a good thing that can be enjoyed, maybe socialize him more in that way? Or is he going to mellow out more as he gets older?
I dunno...

Any ideas?
Maybe I'm just worried too much.. I love my baby. :]

How old is he now? Neuter may help calm him down a little if he's old enough for the male kitty hormones to start affecting his behavior any.

In general though, lots of kittens get a little more independent with they get older. Whether it's just that they don't have to be glued to your side all the time or wanting to be held less, it happens. Just like with real kids.
The other part is just his personality. He may or may not become a lazy cat when he gets older (2-3 years).

Cats have basic personality characteristics, just as humans do, and these vary from one cat to another. One cat may naturally be very outgoing and another may be shy and timid. Kittens are usually playful and outgoing when they're in the safety of their litter with their mother. Perhaps this kitten still felt that way when you got him and now that he's growing up his uniquely individual personality is starting to assert itself. As you know, personality is a combination of nature and nurture. If this cat is programmed by nature to be aloof, then you can only modify that to a certain degree. I'd suggest you continue to hold him and pet him, but only just as much as he wants. If you force more on him, then he'll learn to not like it.

Instead of fitting this cat into a mold that you construct for him, why not just take it as it comes and enjoy his development and the cat that he turns out to be? There won't be any other cat in the world exactly like him.