The pain will be different from a person to another. Piercings? Some won't hurt at all. I know my tragus piercing was painless. As for tattoos, some people can't handle the pain at all, even on spot that don't hurt that much. On bones? It hurts like crazy. I have a small ribs tattoo... well I'm glad it was a small one. Though, I have an ankle tattoo and it only hurt when my tattoo artist touched a bone.
its a needle stabbing into your skin, it's going to hurt. for some people it hurts less, for some it hurts more. and it depends on where you're getting it. i think a tattoo would hurt more because it's done for a longer period of time. a piercing is usually a quick pinch, and depending on where you get it, shouldn't hurt that bad. most of the pain is most likely in your mind, so don't overthink it.