Er... I think if you have to push the needle back with your finger your knitting is way too tight. I just double checked my knitting and I barely brush the needle with my finger after I make the stitch, and I'm not moving the needle back at all with that finger, but pulling it back with the hand that's holding that needle.

(I *used* to push the left needle back with the tip of my finger, and I recall it can get painful. But then I a) stopped using metal needles and b) stopped knitting so tightly.)