If you have to find devices to coax yourself to stay focused on writing, perhaps you should not be writing what you're writing. And if this lack of motivation is a constant problem, perhaps writing is not your forte. I mean, what is the problem? If writing bores you, that is pretty fatal. If that is not the case, but you find that it is hard going and it just doesn't flow, well, what did you expect? It is work; art is work.
Ursula K. Le GuinYou fear them because you fear death, and rightly: for death is terrible and must be feared,' the mage said...'And life is also a terrible thing,' Ged said, 'and must be feared and praised.
Ursula K. Le Guin