Making pizza dough - some basic questions?

I am trying to prepare thin crust pizzas, but I seem to have some problems. I swear the dough sort of deflates once I start working with it. Is this natural?

1. After making the dough and leaving to rise for 1–2 hours, am I suppose to knead it some more before shaping?
2. Does taking a long time shaping make the dough deflate, resulting in a worse pizza?

Maybe more questions coming soon :p.

My pizzas turn out fine, I am just wondering if I am doing something wrong from stopping them being perfect.