Question
My mid-spine hurts whenever I do back bends in yoga. My upper and lower spine are totally fine and pain-free. I often have to do a harsh forward bend rounding my spine to release my spine from back bending pain and my spine makes a popping sound like the vertebrae are unsticking from each other. The forward rounding of my spine hurts mildly too in the same area, mostly first thing in the morning when I wake up. Nothing else hurts - no hip, arm, leg or rib pain, no headaches or dizziness, etc....I am 31.

Answer
I would suggest having an evaluation by a chiropractor.  If there is misalignment, it can cause a change in the mechanics of the spine, not allowing it to move in the proper direction.  A good chiropractor should be able to evaluate and treat this, and set you on a good rehabilitation program.