If the pain is only slight, then you could try taking N2Guard - it does a great job of cleansing the liver and the kidneys. However, if this is real pain you are feeling, and believe me - you will definitely know when your kidneys hurt badly, go to a doc for tests.
usually when guys complain about their kidneys they really are just dealing with pumps
creatine is safe for the kidney's but will effect your bloodwork to give the impression it is straining them, this is why when running bloodwork you should stop the creatine for days ahead of time. blood work is more accurate when you are fasted
Definitely go see a doctor. I don't think it's related to creatine but you may have a kidney stone or something and those are very painful if you pass one!
Creatine supplementation is completely safe for your kidneys but if your kidneys are hurting you should book an appointment with your doctor and get them thoroughly checked out. It could be serious and might be a kidney stone. If you can catch the kidney stone early enough, you can break it through UV light and allow it to pass through the body without surgery.
5-10g of creatine per day is all that is needed to effectively super saturate your body's creatine phosphate ATP energy system. I like the creatine formula ancient strength from n2bm.com. I take 1 serving pre workout and post workout.
The best thing you can do for your kidneys is to make sure you are adequately hydrated and drinking enough water through out the day.