It's almost 4 months that we broke up. But I miss him so bad, and I want him back, I really really love him and I couldn't move on.. but I don't know what should I do.. :S

Who broke up with who? Why did you break up? How long were you together? How old are you.
With details provided better help can be given. If he hasn't moved on, maybe try calling him or contacting him you never know what might happen.

More detail is definitely needed. Is the no contact rule in play? Do you know how he feels about this? Is he moving on? Elaborate on your relationships past and present so we can better help you.

DId you break up with him? Because if you did then you have to be the one to break contact because because he could just as easily be following the No contact rule himself. We need to know more before we can help you.

You must have broken up for a reason. If you really want him back, then let him know how you feel, but it doesn't mean that he will feel the same way.

You can't force him to get back with you if he doesn't want to.

If he doesn't want you back, you will need to learn to accept his wishes so that you can move on with your life. Hanging onto something that may never happen is just setting yourself up for disappointment, as well as prolong pain and suffering.