Before you start grinding anything be absolutely certain that the wheel is fully seating itself in the dropouts if they are vertical dropouts. And if they are semi horizontal then equally be sure the axle is resting on the upper side of the slot. Also check the axle for uneven wear on the exposed threading as well as even protrusion. And check the dropouts for dings or divots in the saddle of the dropouts that could be holding the wheel out of alignment.

If you flip the wheel around it will tell you if there's some sort of minor rim runout or dishing issue or if the issue is at the axle or if it's in the dropouts. Also be sure that you use the same spot of the rim both at the BB shell and at the brake bridge so that you're certain it's not a rim runout issue.