reloads?
If you were shooting reloads, I've had all sorts of problems ranging from difficulty with the cylinder to stuck cases due to a powder too slow. Combustion was adequate from a 6 inch N-frame but from my snubbies it was not. Unburnt powder usually got stuck between the case, cylinder wall, and under the star as the brass didn't expand enough to seal from blow-back. Also happened with a "factory reloaded" case that split.
I second checking for a stuck bullet - shine a light down the barrel - no fingers near the trigger. You may be able to see a bullet in the gap between the cylinder and forcing cone by looking from the side.
If that's not the case, see if you can assist the rotation of the cylinder with your fingers in conjunction with partially pulling the hammer. If you can I wouldn't cock the hammer all the way since you'd have to decock it. Normal rotation should be counter clockwise from the shooter's perspective. A partially backed out case could be causing a lot of friction on the recoil plate, and could ease up when the chamber rotates. Fingers off the trigger, tape the trigger guard if you have to.