I would try a little penetrating oil down the barrel, and at the base of the cartridge first, then use a wood dowel to try tapping it out. If that fails, maybe you can get two flat edge screw drivers into the case extraction grove, prying from opposite sides. A pair of vise grips applied to the case rim, with a twisting motion? Key point - watch out you don't strike that primer.
Sounds like a too long cartridge with the bullet stuck in the rifling, or improperly sized brass. It's Possible when sizing, if you did not lube the inside of the case neck, a tight expander ball could have caused the case to stretch.
If you are uncomfortable with the above, bring it to a gun smith.
larry