Could you tell me if the opposite of the appendix or on the left side hurts is it a sign of appendicitis?

Probably not: The appendix is normally located in the right lower quadrant of the abdomen, so that is where the pain & tenderness localize in appendicitis. Only very rarely is the appendix located on the left side, such as in situs inversus or intestinal malrotation; appendicitis is such a case would cause left-sided pain/tenderness. Colon or left tubo-ovarian problems might be considered with left-sided pain.