Well first I say go see the doc, these forums aren't a full proof medical clinc.
Dry coughs could be a side effect to meds, are you on any right now? Keep an eye if you develop any sever headaches, chest pain, or fever then it's off to the doc's or er to get that checked.
Kidney problems will need to be discussed with the doc, they will run blood tests and urin tests to see if there is any problems with the functioning of them or protine in the urin.
I had really bad lower back pain that would shoot over to my right side, sometimes i'd get this bad upper tummy pain and burning and after the pain persisted for a while I went to the doc and found that my kidney's were a little inflamed. Also I was nauseous and dizzy with a headach, since the kindney's rid our bodies of toxins if they are not working properly we aren't getting rid of all the toxins properly which can make you feel yucky.