Sometimes it can take a short while for the phone to settle down after an update.
If your phones internal storage is close to being filled this can affect the phone.
Check your Play store for any updates.
Put the phone in safe mode which turns off all your downloaded apps and leaves the stock ones alone which can help to determine if an app is causing this situation. If it stops then come out of safe mode and start deleting your most recent apps first.
Clear your system cache files.
Turn off the phone and then from a set series of button presses will take you into the System File Cache and clear those files.
Back up and Factory Reset.
A Samsung Service Centre or Samsung Experience Store will be able to help you further with this situation via a diagnostic.