Look at your answers. Amazing how little we teach kids in school these days. No, they do not feel pain, as mammals do. Rather, they feel pressure, just as your intestines feel pressure, but no pain. After your abdominal muscles were cut, say, to get at your large or small intestine, those could be removed and you would feel nothing close to pain. As well, after the dura were removed from the area encasing your brain, scoops of brain tissue could be removed, and you would not feel it as pain. The pain in those two areas isn't what you have on your skin. And even various places on your skin are not as sensitive as others. You can have a person with two dull sticks hold them an inch apart anywhere on your hand, and that person could tell you that there were two, (or three or four). do the same on the back, and it is not nearly so easy. Fish don't feel pain as mammals do, either, even tho they have a central nervous system.