Your ball goes into a bunker with numerous pebbles and stones and sure enough, your ball comes to rest right in front of a stone. Can you remove the stone?
Good news is that very often there will be a Local Rule that says, “Stones in bunkers are movable obstructions” because it is considered that the stones could represent a danger to players if they are hit during a stroke.
However, during tournament play, the Tournament Committee must allow for the local rule. If there is no tournament rule allowing you to take advantage of the Local Rule then you should not remove the stone.
During the Blue Rock "East" tournament in 2010, an unnamed player was in the bunkers a few times and was the victim of stones behind the ball which is normally not removable. The player played the ball as-is. The player did not realize that our tournament rules sheet for this tournament stated that the player could have used the local rule which DID allow for the stones to be removed. Because the player did not read the rules sheet, it ended up costing him at least 2-3 strokes and out of the money.