I'm a freshman and I'm thinking about being a CS Major. I think it would be useful in research when I become a doctor , but I'm a little worried that it'll end up being useless or too demanding. Should I keep the CS major?
I don't think it would be any more demanding than the bio/chem majors most premeds do. And you are right, if you know how to program and compute things you could potentially have a skill that many medical researchers lack. I say go for it if you're interested.
Take CS classes and see if you like it. I think that coding in general and the math classes you would need to take are all very difficult, but that's just me. Plus, if you like it enough and decide you don't want to be a doctor, CS is a great field to be in right now.
Going CS may actually be an advantage when applying to medical school. Applications are more about standing out and being memorable than anything else. Some schools will see several thousand applications for ~200 seats! In that game, a majority of your applicants are bio/chem/premed majors with good GPAs and MCAT scores and it is incredibly easy for any one of them to get lost in the mix. But coming through with a CS major, now you stand out as a canadate with more academic depth than the usual applicant. Most Universities offer a premed minor which locks up your premed requirements and also gets you in connection with your school's premedical committee for your applicaiton letters. I'll even go as far as saying that the worst thing you can do if you want to go to medical school is be a pre-medicine major for the reasons mentioned above and it is hard to define a non-medical career if health care doesn't work out (just my opinion).