I assume you shoot split finger. This is discussed on another thread in this forum, and what I've recently learned from an insrtuctor is that it has to do with finger pressure, since you have good vertical alignment. Hitting left - too much pressure on the bottom finger. Hitting right - too much pressure on top finger. Nock the arrow, close your eyes, and pull back paying attention to finger pressure - the majority of pressure should be on the middle finger - you can feel it with your eyes closed, but not with them open. This works for me.