I would guess that your lack of concentration is due to boredom, maybe because you're working on stuff you don't care about. If circumstances requires you to w

I would guess that your lack of concentration is due to boredom, maybe because you're working on stuff you don't care about. If circumstances requires you to work on uninteresting things, putting the distractors out of easy reach can help you grind away in the short term. In my own experience, I needed to change industries to work on things I found more interesting.