I got some code that is Open Source published under, GNU AFFERO GENERAL v3, my question is can I re-licenses to so something more strict with sharing? And what license could I change it to, to be more strict?
No, you may not. If you were to change the licence, that would constitute a modification. The AGPLv3 is clear about modified versions; in s5 it says that you
may convey a work based on the Program, or the modifications to produce it from the Program, in the form of source code under the terms of section 4, provided that you also meet all of these conditions:
c) You must license the entire work, as a whole, under this License to anyone who comes into possession of a copy.
Interestingly, the AGPL is already regarded as one of the strictest free licences when it comes to sharing; elsewhere on this site you will find people arguing that the AGPL is so strict that some corporations refuse to allow employees to use any code so licensed. I find myself wondering what kind of restrictions you were hoping to add, and yet still call your program free.