Is it okay if don't want my roommate to make changes to our apartment?
Why don't you want your roommate to change things in the apartment?
He changes things that are mine and things that I like.
I know that you like things to be in a certain place, but your roommate also shares the apartment and has a right to have what they want as well. You should speak to your roommate and the two of you can decide together where to place items and set up the apartment you share.
Nah that's not going to happen.
Part of being a roommate is accommodating one another and making compromises. If you can't communicate that to your roommate, then it would be best to move out and find another way to live on your own.