I miss him

I have breaked up with him over 2 months. I didn't feel so sad in this period of time . But I don't know why these days I miss him very much. I sent lots of messages to him, but he didn't sent me back. Could it be said that we can't be friend after breaking up? I want to find him , but I don't have courage to call him. I' afraid of listening his voice. What can I do?