@Gee30 some more infos will help us debugging your problems. Do you use a screen protector? Are you moving apps to the SD card? What happen if you reboot your phone in safe mode?
What I suspect is that the phone freezes due storage issues (internal/external) or low memory that trigger the system to use virtual memory which usually slow down the phone. So yes, please reboot your phone in safe mode and then without SD card (if any). If in safe mode works better then the issue is that you have too many apps installed or that an app is using too many resources. If you your phone works better without SD card then the issue can be hardware (the sd card per se) or software (too many apps running or an app installed to SD card).
The screen may freeze and stop working due the fact your phone freeze but can be also an issue related to a bad screen protector.
