Z10 wont unlock.. frozen but not really..

Hey everyone,
lately I've noticed my Blackberry every now and then after I holster it and it locks, I take it out and it wont unlock. I cant swipe or get the password keypad come up. If i press the power button, the screen goes black and vice versa.

Only way I can get a response is to reboot the phone. anyone else have this issue?

I have less than a handful of apps on my phone but I am wondering if one of them is causing the issue.


Thanks