Are you allowed to tell a doctor you don’t feel comfortable with an exam?

So I’m due for some sort of immunization shots soon. I haven’t been to the doctor in about 3-4 years because I honestly never get sick. I’ve never had a sickness that lasted more than a few hours, even as a baby and toddler. My parents just think it’s silly to pay so much money for them to tell us I’m perfectly healthy. Now I’m not going to argue with my mother about going to the doctor, even though I feel it’s completely unnecessary. But last time I was there the doctor decided to feel between my legs and my chest. At the time I didn’t have anything to feel weird about expect for the between the legs thing but I’ve..matured since then. If they try to do anything this time I plan on simply saying I’m not comfortable but I’d like to have something to support me if they try to force me. Some sort of law that allows me the ability to say no to those kind of exams. My doctor is known to be very rude and unkind when it comes to not following her directions, when I was 4 she locked be in a room because I struggled during a shot. So does a law exist that can help me in this situation?