First of all, don't do anything until you have THOROUGHLY cleaned underneath the extractor with a good stiff brush. (Plastic bristles are fine, if stiff.) A tightly-fitted sixgun can get really hard to shoot, SA or DA, when a bit of fouling keeps the extractor from fully seating in place. One of my GP100s can really bind up with just the tiniest amount of fouling. I have other sixguns that will do this, just not as bad. I learned to keep an old toothbrush in my back pocket during long range sessions and shooting classes.
To be clear, this is NOT a symptom of a poor maintenance. It can happen to a very clean sixgun. How does it happen? Well, we generally hold our sixgun muzzle-up, during reloading, to allow the cases to fall free. Well, along with the cases, debris from unburned power also falls free, and some of it lands on the underside of the extractor. As the extractor springs back into position, it catches this trapped debris, and packs it down. If the pieces of debris are large, or if enough small pieces accumulate, it can make the cylinder harder to close, and once closed, harder for the action to cycle.
FWIW, two of my older GP100s, late 1980s/early 1990s era, have grunge grooves under the extractor, to allow for fouling.
Secondly, if you feel up to it, clean out the action. There could be a bit of fouling, or a small bit of metal that came loose, tending to gum things up. Nothing wrong with letting Ruger look at it, but shipping is expensive.