You create everything out if yourself. 
You create all sorts of subselves out of yourself and via the numerous subselves you experience others, worlds and minds. 
You choose to forget that you are everyone and everything. 
Instead you choose to be one specific character of your infinite creation and you experience the unhappy sense of separation and isolation. 
Thus you create your own yearning for the return to your wholeness since your true nature is happiness and happiness does not know unhappiness and can only point to the reality that it is.