Occasionally my carpal tunnel acts up and I found wearing a wrist brace keeps everything lined up correctly - that may help your wrist. As far as poking your finger underneath - put something over the finger. I've seen leather thimbles, plastic things that stick on your finger....I have found that I learn how far to put the needle thru, and i barely stick my finger once i get into a groove.
Don't worry about teeny tiny stitches - even straight stitches look just as good. If you can't eyeball straight lines - draw the line.
I hope you can find out what works so that you can enjoy the quilting process.