Which group in Pakistan doesn't have grievances or issues? The question is whether they are justified or not. Pakthuns in the Northern Areas blend into the region instead of sticking out as foreigners. I remember seeing seeing flatland Pakistani tourists on travels/honeymoons/school trips who acted like complete foreigners in their own country. Ofcourse they would stick to the 'touristy places' like Chitral, Hunza, Gilgit etc.
You just can't make broad political statements like believing that Iranic peoples are somehow expected to stick together because of some cultural commonalities. If that was true, I would venture to say that most Pakistanis were in deep denial vis a vis India. I don't speak for other Iranic peoples but I do know that Pakhtun and Baluch fall under supratribal societies which is remarkably different from other Western Iranics.
You just proved my point. People's similarity or close proximity doesn't account for much when it comes to fighting over resources.