Actually, I don't think that deflatinig the lung hurts, although there may
be some pain when the pleura (lining of the lung) is injured.  (The lungs
won't rapidly be deflated. The lung is made of millions of tiny air sacs.
Only a few would be injured. What is more of a concern is that air would be
sucked into the chest (outside the lung) when the person breaths in, but
when the person breaths out, the air would be trapped. This is called a
pressure pnuemothorax.)

However, broken ribs can be extremely painful. If you break your arm, you
can put it in a splint. The ER or orthopaedic surgeons can put it in a cast.
But you can't put your ribs in a cast. The ribs are constantly moving as you
breath. You can't stop that without killing someone. Until the ribs begin to
heal (weeks at least), every breath hurts.

http://athletics.cerrocoso.edu/sportsmedicine/chest_injuries.htm

You can also search google for chest wall injury or broken ribs.

Jeff