I want game to explain to me why my Qunari has never even followed Qun, what happened to him to make it so? Was he raised by some humans or what? All I found was "If you play as Qunari you have never followed Qun in first place" and that to me is mindfuck considering all Qunari lore.
Is there even lore for Qunari that has never even followed Qun?
Yes. There are plenty of Qunari who don't follow the Qun, they are called Tal-Vashoth and generally work as mercenaries (which is what your Qunari character is before they become the Inquisitor). They were mentioned by Sten in Origins and you meet a whole bunch of them in DA2.
Also, it would be incredibly difficult to have a Qun-following qunari as the Inquisitor. The Qunari are basically defined as having a particular and singular purpose in life, which is their way of 'satisfying the demands of the Qun'. If that purpose is suddenly changed, then most Qunari would kill themselves rather than go against their Qun-defined purpose. This happens in DA2.