Kevin Costner is getting candid about having kidney stones while filming Hidden Figures. The Yellowstone alum, 69, revealed he was on a morphine drip while making the hit 2016 flick but managed to finish the project despite his difficult health hurdle. “I’ve never worked drunk on a set. I’ve never worked high on a set, but I was on morphine the last two weeks that I worked,” Costner explained in a recent interview. “I had kidney stones and I worked ten days under an IV drip. I don’t even know how. About three days of it, I was normal and then something happened to me.” “I’ve never missed a day…