Do you need help removing the forend from your L.C. Smith shotgun?

Open and close the action to cock the hammers.  Use a hardwood wedge (half of a wooden two-piece spring-type clothes pin works well) and firmly but gently push it between the tip of the forend and the bottom rib between the barrels. Assuming the gun has manual extractors, this technique should pop it loose and not mar the metal or wood surfaces.

If the gun has a roll type latch release; the same technique can be used, but you must also hold the roll in the un-latched position (forward) while inserting the wedge.
It's possible that the forend J-spring was bent when someone attempted to replace the forend with the hammers un-cocked, and an experienced L.C. Smith shotgun specialist gunsmith should take a look.