Dont worry, this is totally normal for a hamster to do! Many hamsters like to store nesting/bedding materials in their cheeks and move it around to where they are most comfortable, (commonly moving it to their sleeping area) It sounds like your hamster is just curious though and is playing around with the material. My hamster does this with her bedding every time I change it out at night too. In the morning, I'll see she moved it to a different part of her cage.
So you're hamster is probably just curious and you shouldn't really have to worry.
Hope this helped!