Not "riding straight" is symptomatic of any of a multitude of problems, not limited
to frame and fork alignment. Wheel dish and centering come to mind as well as
headset play.

In the case of wheels, anything that causes the rims and tires to not track in
line and on center with the frame centerline will generally throw you off a little.

If your problem began when you straightened the fork drops to align them (?),
then if I had to guess, I'd guess that you yanked one of them farther outboard
from the centerline than the other one. But it's only a guess.

It's certainly possible to have a perfectly aligned fork, put it into a frame that
is either misaligned or has a tweak in the steering head and still have issues,
so you might want to get someone to look at the whole thing as a unit.