chevy s15 clutch

I have a 86 s15 4x4 truck. I put a new engine in it and the clutch started messing up. I have no clue what it is. The clutch looked ok when i changed the engine. The fluid levels are fine but it is hard to take it out of gear or put it in another gear without pumping the clutch pedal. Is this a cylinder of some sort bad or what. help please. Could it be that i bent the pressure plate prongs on installation of engine??????????????