Did you blow the primer(initial lubrication) out of the atomizer first?
If you did, how are you hitting it? It sounds (correct me if I'm wrong) like you are drawing hard (as if you were trying to pull as much smoke from a cigarette as you could)....but with PV's, the draw should be slower and easier(as the atomizer needs to heat up in order to make your vapor) kind of like drinking from a straw.
Did you get the 510 with a manual switch? If so, try pressing your switch down for a second before drawing on it, it might help you get a better/easier draw.
I hear with auto switches, you should use a primer-puff(for the same reason), so if you are using an auto, hit it once real quick to turn the atomizer on, then again slower/deeper to get the draw.