I like the John James big eye quilting needles because I can thread them. The holes on regular quilting betweens is just too small for the thicker hand quilting thread to go through. Maybe it would be easier if you use a double-pointed needle, especially since you're trying to sew through denim.
http://www.amazon.com/John-James-Twi...457885&sr=1-14
I know how hard it is to keep on keeping on sometimes. I had carpal tunnel syndrome in both my hands and couldn't crochet more than a minute at a time before the pain became unbearable, then had to rest my hand for several minutes. I hope you find a needle that works for you.