I want to go to medical school but I can't decide on what I should major in in college?

While you can "major in anything," unless you are a prodigy you will have difficulty taking the MCAT without sufficient chemistry and biology. You do not have to major in biology, though, as there are other interesting majors in the science field. Go through the college class for all the life sciences--biology, chemistry (you actually use this a lot), bioengineering, microbiology, even pre-pharmacy. A psych class or two is fine if you like the subject, but take a statistics class if you take beyond the foundation class. That will help you the most.

I'm a third year med student and I can tell you that you should study what you are passionate about, that's what medical schools admire most. So long as you fulfill the required scientific courses to get into med school (do a pre-med course too) and take the MCAT, they will love that you have dedicated yourself to something you are passionate about, and not just stuck with the science courses because you thought you should. So even if you want to study English or Theater, you should if you really want to. =)

One thing I will definitely add in here is that if you feel you are not very strong in the sciences, no matter what you major in it is not going to help you in the end when you get to med school and are struggling. But you might end up getting weeded out with your MCAT score or the grades you get in your science courses if you don't take them seriously. Definitely pursue what you love first and foremost, but make sure you do very well in your science courses to the point that you are prepared to take that MCAT.... Otherwise, try taking courses your first year that share prerequisites for both sociology and psychology and take some premed courses just to give yourself an intro. If you decide to major in a nonscience major, I would definitely advise you to try to take some upper level courses here and there just to help you later on.

I don't think med schools require that you have a specific major as long as you have completed all the prereqs for their school. It'd probably be a bit easier to complete all the prereqs as a bio or chem major, but do what interests you the most.