A man can spend several hours sitting cross-legged in the same position if he knows that noting prevents him from changing it; but if he knows that he has to sit with his legs crossed like that, he will get cramps, his legs will twitch and strain towards where he would like to stretch them.
Our day-to-day lives are pretty chaotic. So in terms of the writing part, you have to get pretty disciplined about finding quiet moments and making sure you're making time for the art side, on top of all the time-consuming business side.