I have successfully straightened many frames like that one. You may find that the front downtube on the right side is bent inward slightly, pulling the lower side of the head that direction?
The ones I have fixed were all hit by a car or truck bumper in those tubes (parking lot accidents, or a garage hit), so pushing them back out with a bottle jack straightened things right up again. The bikes are still on the road, handle fine, wheels in line.
Frame-and-axle shops with Bear Alignment equipment that is used for straightening the older Ford pickup truck I-Beam front ends can also twist the head itself for about $50, if it is in the upper tubes somehow. After this fix, have the joints where the head meets the tubes rewelded a little bit, as the welds will likely crack in the twisting process.