I have 4 kidney stones.. i would like to start using a protein shake for working out. would i be better off to use a whey or soy because of my kidney stones?

None: You should avoid high protein diet in most of the kidney stones.

Kidney stones: Animal protein is the riskiest protein. It is more acid and the acid releases calcium from bone. Soy has some oxalate, another risk for stones. Whey has no oxalate. I think whey is a bit "preferred". Keep total grams per day of all protein less than 60 gm. Drink 4 liters fluid per day. Include 4 tblspns ReaLemon extract per day. Minimize animal protein and oxalate foods.