I do suffer from a similar condition, being able to get in the mood can be quite challenging.

I found that whenever I need to get started on some brain intensive task, be it writing or designing a piece of software architecture, being out and about in a social space (a coffee shop, a pub) works wonders.

I have both a lack of distractions (mobile on silent and out of sight) and a drive to do something instead of staring at folks awkwardly.

What's more surprising for me is even in a noisy environment, I still maintain my focus. I tend to favour pubs, so maybe it's the alcohol working its magic :)