What Does A Painful Spot On Tailbone Indicate?

hello, I have a painful spot about 3 inches from my tailbone to the right (in my buttocks) it is painful to the touch it feels like cartilage. if I can explain it in a funny way, it s like a piece of gristle. (Best way to describe it) it s under the skin. Its like a hard tiny rock but it s painful to the touch. Any ideas or explainations would be greatly appreciated. No this isn t a joke. It s very uncomfortable and mind boggling to say the least. Thank you for your time.