Just what you needed, a Smart arse answer.
Seriously though, if you have problems staying focused, lock the phone in the trunk of your car and leave it there until the job is done.
I used to work for an employer that made us lock all cellphones in the locker as soon as we got to work.
Why? Because he needed productivity, not a bunch of folks wasting time on cellphones.
The only calls allowed were to the Main Switchboard and Life or Death only.
Honey Do items belong at home, not at work, or at school.
It has not been all that long since the only phone available was the one in the house, and the world got along Just Fine w/o a bunch of folks talking on a phone all day long.
Seriously, you just need to retrain your mind as to what is important.
And a phone is NOT IMPORTANT, not if you need to work.