Is appendicitis painful and can it be asymptomatic or would you know something is wrong?

Always painful; asymptomatic appendicitis is exceedingly rare if it occurs at all.

Appendicitis is usually painful, sometimes severe, and sometimes accompanied by fever or chills. It would be unusual for it to be asymptomatic, and it is usually clear that something is quite wrong. If you have pain in the right lower quadrant of your abdomen, it is appropriate to see your doctor or go to the emergency room.