Ex’s have you ever gone back to ex? How did it go?

I’ve been out of my relationship with my ex for 4 months now and I miss him terribly. I hate the reasoning behind why things ended I don’t feel it was a good enough/ not a reason at all. So I feel like I have no closure which is probably why it’s hard for me to forget about him. truthfully I really want to message him and see how he’s doing and that. I just miss talking to him, he was a part of me then just left. I’m torn if I should bite the bullet and message him cause you never know he could be feeling the same thing. I don’t know and I highly doubt it but you just never know till you try. Has anyone gotten back with an ex / made contact with them after a break up. ? X