Is appendicitis always painful and tender?

Almost: I try very hard to always "always" and "never." Yes I've seen painless appendicitis rarely but there are usually other clues. History of anorexia, constipation and malaise are prominent. Elevated WBC with lseft shift is prominent and even the "painless" abdomen when approached carefully will demonstrate some rebound tenderness and guarding. Fortunately we do have CT scanning - about 90% accurate.