Why Does My Kidney Hurt And Feel Like It Is Contracting?

Like vak says, it could be dehydration, or it could also be kidney stones. Either way, drink plenty of water. If you notice any blood or pain in urination see a doctor asap, the stones may have caused damage. But usually the pain will be almost unbearable before that happens. When i had mine the nurse said mine were as big as hers had been and she said she would rather go through child birth again than through kidney stones ;) lol! Most of the time they're pretty small and pass fairly easily with little pain.

You are probably dehydrated. Drink some water a few glasses and see if this doesn't help, if not you may need to see a Doctor. In most cases you need fluids as dehydration affects your whole system drastically.