Please i need to know what the appendicitis synthoms (sorry for my grammar) are or what could this be..?

Well my mom says she has pain on the lower right side of her stomach and back, her right leg hurts up to her knee and two days ago when it stared she felt like she wanted to vomit but she only burbt (again sorry for my grammar) and she felt something sour in her mouth. I Think she is going to the doctor 2morrow but please if you could help it will be great. Thanks!