i have to agree with a few of posting predecessors; clearly a paddling issue. you're not generating enough speed and getting hung up at the top. with the longboard you can get on a wave with a few strokes; a boogieboard can drop in late on almost anything without getting pitched; a shortboard needs a few more grunts to travel faster than the wave itself because when you pop up you slow down. paddle as hard as you can then paddle harder. you'll start getting them.