I can certainly relate to that... my brain seems to be all over the Universe, most of the time. Hence I take a lot of notes when ideas come up!

I understand the issue with "branching" (what I call it when one thought leads to another, which leads to a third and fourth one) and often deal with that. Were it not for pretty effective voice-to-text technology, I'd probably never get anything done... but for the moment I make a lot of "quick side notes to myself."