I'm still in love with my former friend yet he has rejected me for over 3 years now
Have you done anything for them to reject you?
Yes, I did something terrible to him, I told him that his cooking tasted bad once
You can't force chemistry and attraction, and you should respect the other person's decision and also, in turn, figure out how to move on yourself. Try to talk to other people and see if you can connect with anyone else in a romantic way.
It's so hard to move on when someone you love has rejected you and I can't be friends with them any longer.
I know it's really hard because you just love them so much, but sometimes things aren't just meant to be if they still don't like you. You might be clouding your present and future by constantly focusing on them; wouldn't you want to find someone who actually cares about you?