Did you get new tires recently? I had this same exact situation on my e92 328. But it was after I had new tires installed. Same brand and spec as the outgoing set. They even swapped them for another of the same. Still had the problem. So I borrowed some stock wheels and tires from a friend. NO Pull.
Went back to the tire shop, switched to a different brand tire, and everything went back to normal.
Still no eplanation other than that it was a bad run of tires or something.
Oh well. Good luck.