Hello , My Name Is Kylie And I Am 13

Hello , my name is Kylie and i am 13 years old..I have been having real bad sharp pain in my lower left side of my stomach.. It hurts really bad where I cant even move. Ive tried a heating pad and it don't work.. I have cried a lot because it hurts really bad. I have a little headache. I don't know what to do because it hurts so bad. Should I go to the ER or a doctor .?