Try booting into the Recovery Menu and wiping the system cache partition, which can sometimes help issues like this. No personal data will be lost.
Follow the instructions in this video starting at around 1:40 to boot into Recovery Mode. However, make sure you select wipe cache partition, not wipe data/factory reset. When the cache partition is wiped, then select "reboot system now."
That seems to happen fairly often with Samsung devices. I don't know if they block the ability to wipe the cache partition, or if there's some other fault that occurs. Do things improve after rebooting? If not, you might want to consider a factory data reset.