My friend is wanting to know if its dangerous to have small kidneys? she has been having a lot of back pain, chills and shortness of breath.

Lungs?: Kidneys vary in size a little. What do you mean small and why are they small? If she has a chronic kidney disease and her kidneys are small as a result of that it could be related to her current symptoms. If she has mildly small kidneys and normal function this is not likely relatedat all. I wonder if her symptoms are more related to her lungs which can produce pain, chills and short breath.