Sounds like you're doing exactly what you thought, raising your shoulders too fast in relation to your hips. When I see this, I have people run through a few triples of clean deadlift to position (jsut at the knee). Usually clears it up.
Could also be starting off the ground fine, but rushing into the 2nd pull transition too early. Either way, if you get some practice in maintaining your hip/shoulder angle coming off the floor, all should be well. Only other option I see is a bad start position.