can i sue if a drunk driver ran into the back of my car and i had to go to the hospital?

You'll want to contact a Personal Injury attorney. Those of us that handle these type cases would charge what is called a "contingency fee." That means the lawyer only gets paid if you get paid. With respect to the wreck, whether anyone will take your case depends on whether the person that hit you had car insurance. If so, yes, you can sue. If not, you can still sue, but there will likely be no money to go after.