Time's very lucid cover story asks why medical bills are so high:

Yet those who work in the health care industry and those who argue over health care policy seem inured to the shock. When we debate health care policy, we seem to jump right to the issue of who should pay the bills, blowing past what should be the first question: Why exactly are the bills so high?

Time has no answers but asked a lot of the right questions.

Why are the bills so high, and why is there nothing we can do to control the costs?