Are you sure that it was not off-center before the recent work? Sometimes we become hypersensitive in situations like this, and we start noticing things that were there even before. (As an example, after some major transmission work I noticed a little buzz that tracked the engine RPM. I thought it was the tranny, but it turned out to be the power steering pump. I had just not noticed it before.)
If the steering wheel is off-center AND the car tracks straight, then you would need to get the alignment re-done... or learn to live with it (it IS bothersome).
OTOH, if what you mean is that you have to constantly steer to one side just to keep the car going straight, that might require a realignment, or it might be fixed just by making sure the tires are properly inflated and/or by rotating the tires.