There's not nearly enough information to actually figure out the problem here. As such, all of the following are merely possibilities. It's up to you to figure out what the issue is.
Perhaps he feels smothered by the relationship. He may like you, but he needs his space away from you, too.
Perhaps he feels like you aren't contributing enough to the relationship. If "he doesn't text me, he doesn't call me", are YOU making any effort to get in touch with him?
Perhaps he is stressed about something in his life. Before he can be comfortable with you, he has to be comfortable with himself. Chances are, this will go away.
Perhaps you two don't have enough communication in your relationship. He might feel that you're difficult to work with, and you might feel the same about him. Ask him nicely what the problem is, and don't be accusatory. Be willing to help him. Work at a solution, not on placing blame. If he is unwilling to communicate with you, then it's best for you just to move on.