Syrian Compulsive behaviour- Help?!

[Katieleo]

Hi all, I need a hand as I'm concerned with my Syrian hamster, Leo.
He's nearly 6 months old and he's starting to show some odd behavior - mostly never running on his wheel and always wanting out of his cage.
At first I thought it was because he had gotten too big for his cage as he was gnawing at the bars so I bought him a much much bigger one with plenty of room and toys. But he still seems stressed, trying to get my attention to let him out into his ball or to run around my room in general. But he has two wheels that are not broken and doesnt use them.
He's friendly and rarely bites but he does laps in this three story cage cage often climbing up and then coming down the ramp and then does it again and again. I am also certain the fur on the back of his neck is getting thinner and I often see him grooming himself quite vigorously it also is starting to have a shine to it which i didnt think was normal. He is a long haired hamster but I'm certain its thinning out.
When he's not in his ball he will mostly sleep, I have two hamsters and he's currently asleep whilst the other is on his wheel and its 2am.
I did wonder if my other syrian is what could be stressing him out, there in completely separate parts of the room but he seems oddly sensitive to hearing the other one, Lenny. Maybe because he can hear or smell him? Is it possibly worth moving the other to a separate room? I read up on such things as hamsters having ocd and compulsive behaviors but i couldnt find loads of info, what I did find his behavior seems to link.

He sleeps alot and I'm not sure if he's bored or stressed or anything. He's extremely friendly and curious but his behavior and his fur is concerning me and I think i might take him to the vet but I thought I'd ask and see if anyone knew what could be responsible.