I agree with the above poster.
As for the kidney stones there are many things that can produce stones. First you need to find out what type of stones you are making. anything with oxalate is not good for people who form stones this also includes chocolate, beans, blackberries, nuts, strawberries, spinach, the list is very lengthy.
It's a fine line and a hard one to follow sometimes. Unfortunately some people are prone to stone formation.
As for the nodule, as lonestarguy mentioned check with your doctor, get another opinion if you are uncomfortable in any way with what your current doctor is telling you.
Good Luck