I hate to repeat the obvious, but, when you have unusual pains, you should call your doctor. If you can’t afford a doctor, there’s sure to be a free (or low-cost) clinic in your area.
A pain in the kidney region could be a symptom of any one of about three zillion different causes, ranging from an allergy to some ingredient in the ice cream to developing kidney stones to impending renal failure to warning signs of cancer. You can’t really expect a diagnosis from the Message Boards, nor even a listing of the most likely possibilities.
Besides, are you willing to risk you life/heath on a list of “most likely probabilities” ? What if you’re one of the exceptional cases, and not a “most likely”?
So, please, Carnac, call a doctor.
I’m closing this thread because you’re not even asking for a list of “most likely possibilities,” you’re asking “what is it?” in your specific case. Asking for a medical diagnosis on line is against our rules and against common sense.