Pet hamster help i have 2 chinese dwarf hamsters (same litter) and they get along but wen ones sleeping?

in the bedding the other one goes in and in a few minutes later he is running it the wheel he ran in it all day and night but never goes in the bedding did he get kicked out from the bedding our do i need to save for a bigger cage so he can have his own space to sleep or is it just that he doesn't want to sleep int the bedding or is he just hyper there both Pretty young i have a started 2 lvl cage with a decent amount of space what do i do plz help and there's no frighting only play frighting they weren't squeaking or scratching or bitten they were just lightly hitting like u would do whith your brother or sister wen u play fight