What really helped me improve my typing speed is...sitting up straight, feet to the floor, elbows at my side, eyes only on the text and never on the keys, doing exactly what my 8th grade teacher taught me to do.

When my fingers hurt after too much time on the keyboard, I... That is the most ridiculous statement anybody could say! No matter how fast a person can type, their fingers will NEVER hurt. That's like saying that a person's lungs hurt from breathing too much.