Hey, i have 20 mastery pages and its hard for me to keep track of which mastery page belongs to which champion, there should be a way to move your pages around so i can group the champions of the same lane together. For example, I want to have my first few pages be top lane champions, then after i have all my top lane champions the next few pages can be mid champions, etc.

Post in the PVP.net forum. This is not in-game.
There has already been a lot of the same suggestions made as well. Try looking for a post similar to yours before making another. It will help keep discussion and support in the same place and get more people who share your opinion together.

You know you can rename the pages right?

He's talking about moving them around so that pages for the same lane are in the same spot, instead of having a mid page, then bot, then top, then another mid and so on without having to remake all the pages.