I have a bad cough and now bad kidney pain what should i do?

Cough: First I would ask if you have a temperature or if you cough is productive? And is the pain in your back in the center or truly in your "kidney" area(upper back to sides) Because with a fever, productive cough, and pain in the upper back you could have a pneumonia. I would strongly suggest that you are seen by you doctor and have a really good exam. In the meantime rest, drink plenty of fluids.