A year ago we had a barrel problem with my wifes S&W Lady Smith (Model 642LS 1 7/8" barrel, for her self protection). S&W replaced the barrel, but, the trigger pull is now so hard she cannot pull it. I figured it just needed to be used so over the last year I put about 200 rounds through it. The trigger pull has not changed. Now I am considering replacing the trigger spring, however, I have heard that also affects the firing pin action. I am pretty good with mechanical things, but, I don't know diddly about this. At this point in time my preference is to have a knowledgeable, reliable gunsmith do the work. That way I have a warranty. The other route is just to sell it and replace it with one she can fire.
What am I looking at to reduce the trigger pull? Can I do it? Is there extenuating circumstances I need to consider? I see there is a sticky about where to find parts, so, that question can be answered easily.