Sounds like your device is overloaded with apps or you have an app intalled that is misbehaving.
Maybe your device is short on memory.
Anyway, you can start by checking which apps are most used.
Goto your apps panel, tick the 3 dots in the upper right corner and tap on Sort apps.
Find hardly used apps by scrolling all the way down.
Drop those, delete them.
Clean up your machine.
One more:
If this freezing happened recently, you can sort your apps on date installed and delete the most recent installed apps.
One of those might have caused your freezing device.
Once again: clean your machine.
(and report back what caused your problem, so others can learn from your experiences)
