No, you do not have to major in a science to go to medical school. This is one of the biggest misconceptions among pre-meds. Majoring in a science does not increase or decrease your chances at obtaining admissions into medical school. Medical schools care deeply about the grades you received in the classes you took. Apart from the science classes required to apply to medical school, medical schools do not state you have to take more science classes.
To learn more about this question, read You Can Major in Anything.