The Potcake, also sometimes referred to as the Island Dog, is a mixed-breed dog found on several Caribbean islands. The name comes from the staple of its diet: the dried cake which forms at the bottom of pots used for cooking and reheating.
Amongst other conditions, a renal ultrasound scan can detect kidney stones, cysts, tumours, congenital abnormalities of the renal tract (these are abnormalities that have been present from birth), problems of the prostate, effects of infection and trauma of the kidneys and renal tract. Full Bladder.
You would need to have an imaging study of your kidney to detect a bruise (like a CT scan or an ultrasound). I am not suggesting you do this because even if there is a bruise to the kidney (and I doubt there is) there would be no special intervention if pain was the only problem.