Very few women ever see a breakup coming and if you are one of them, that is why it is so hard to take. You thought everything was fine and then he told you he wanted to end things. You were stunned and started to cry and ask him why. Of course he wouldn't tell you. He was just in a hurry to leave. Now you are asking "how can I make my ex boyfriend chase me again"?
The biggest problem you face when you are the one left behind after a breakup is that he is in control. Your ex boyfriend is sure that you want him back. That means he can just sit back and watch you chase him and he can reject you. This makes a good situation for him but a very bad one for you. To make him love you like he did before the breakup, you have to gain control.
When you are in control you can make your ex boyfriend chase you again. But you must keep a firm grip on your emotions and not let your heart rule your head. There will have to be a cooling off period before an contact should be made with him anyway. That should give you time to calm down and start thinking more clearly.
You have to take back the control from him without him knowing what is happening. The best way to do that is to ignore him and move on with your life. Spend time doing things you like to do. Go out and have a good time with your friends. The whole idea is to let him see that you can have a life without him.
Soon it will be clear to him that you do not intend to chase him.