I have Shimano brakes, and I have them double shimmed (two sets of shims per brake lever). I have really tiny hands. It really helps.
Also, if you are on a hybrid, does that mean you have flat-bar handle bars? When I first started biking, I had a mountain bike that was never properly fitted to me. I ended up with loads of pain in my wrists and elbows.
Later, I got a road bike (Specialized), and the bars have a wonderful, curvy shape...even more curvy than a lot of other road bikes I've seen. Those bars, including the bar phat gel underneath the tape, have eliminated my elbow and wrist pains. I know you have a pre-existing condition, as you mentioned, but maybe more options on your handlebars would help?
"The best rides are the ones where you bite off much more than you can chew, and live through it." ~ Doug Bradbury