Try doing a factory reset.
IT WILL DELETE ALL YOUR DATA SO BACK UP EVERYTHING TO A COMPUTER OR MEMORY CARD
Go to settings
Look for Backup and Reset
Try to perform a backup to your memory card
Select Factory Reset/Data Wipe
If you can't even get to the settings you can go the bootloader way
Switch off your phone
Press the power + volume up button or power + volume down button.
The phone will boot onto a black screen with blue or yellow text.
Use the volume buttons to navigate to Factory Reset/Data Wipe
Use the power button to select
The phone will erase everything on it and reboot just like a new device. This should help improve the freezing issue