My back hurts when I breath in wher my lungs are what is it?

Multiple. There are multiple reasons to have back pain with inspiration. The most important would be an issue with the lungs, like asthma, copd, pnuemonia, or pleuritis. There can also be issues with the structures of the thoracic region, including the ribs, muscles, and the thoracic spine. An examination with your doctor would be recommended.