I believe that when a man is distant that the best thing is to leave them alone. Find things to do and date. The more you go after him whether it is the phone, email, texting, etc - the more they are likely to think you are not in control of your emotions - Most particularly if you are asking them what is wrong, or accusing them or anything that would put them on the defensive. It doesn't take much to put them on the defensive.
Think about it - if you even had a friend who acted that way (bothering you) wouldn't you try to avoid them? Take a break and do some things that you enjoy and let it go. Chances are he will wonder after awhile what you are doing and how come you can just go on with your life and forget him.
You are a special person and don't forget it! Special people don't need other people to feel special.
I have a guy-friend who I had a heated discussion with and although I wrote him one email afterwards, the email was without emotion. I did not accuse him, or make any references to what he did or didn't do. He had misunderstood something I had said and the conversation got out of control - I honestly didn't understand what the argument was about but stumbled around and finally got frustrated. I wrote the email 2 days later to present what my statement had meant. Maybe an email to a sweetheart like that could be in order if you are cooled off - but to bug him or expect something from him....not cool. NEVER sound or present yourself as desperate or clingy.