Hey my son never really likes to tell me or his ...

You did not mention his age (it is a very imp[oratnt factor).  Assuming that he is a teenager or an adult there are several possible reasons for that:
1.  He did not receive a proper responce (in past events). 
2.  He is an introvert.
3.  He is extremely shy. 
4.  He has low self esteem / confidence. 
5.  He is afraid that you'll not understand him. 
6.  He did something wrong and does not want to expose it. 
7.  He is hiding a secret (could it be that he is gay ?).
8.  He doesn't want you to know with whom he is socializing. 
9.  He is using drugs (and wants to hide it). 
10.  He is seeing someone that you'll never approve. 
11.  He does not trust you.
12.  He does not believe you can (capable to) help him. 
...................   Just few to mention. 
Be smart and sensetive and try to find out what is (are) the real reason (s).  Build the trust between you and him, only if he trusts you he'll open himself to you and communicate.  TRUST is the key word.