People say my ex misses me but he acts as if he never wants to be with me. And I feel like he hates me. What do I do. I want him back.
Missing someone and wanting them back are two different things. Move on.
He may try not to show it so that he doesn't look the desperate one. Try to read some of his body languages, the way he talks to you and his behaviors towards you. You can also ask some of his close friends if it is true that he misses you.
make him come to you, show him that you truly need him, and if he really loves/cares about you he'll come to you.