My daughter also has an issue with going to the doctors. A couple of months ago I suspected that she might have a bladder infection (saying she had to go to the bathroom 5 min. after she was just in there, getting up in the middle of the night, etc.). When I told her I needed to take her to the doctors, she of course got very upset. I called the doctors, explained the situation, and they let me run over to the office to pick up a sterile cup for her to go in, which I brought home. (It was a little inconvenient for me but much easier than dragging a screaming kid into the office.) When she went in the cup, I then ran it back to the doctors office and they did some kind of quick test which showed that it probably was a bladder infection. Gave me a perscription and called a couple of days later to tell me that it was confirmed. The doctors were very understanding and willing to work with the problem. Try and give your daughter's doctors a call, they might be willing to do the same for you.
Good luck!
As you sense, your daughter's behavior is in part due to habits of interaction you have created. The good news is that you can change your behavior, and in the process yopur daughter will change as well. As I often say to parents, your child will change to the degree that you can change. Most, not all, parent-child interaction problems are fundamenatlly the result of choices the parent makes. Now, it also sounds like your daughter may have components of her behavior and emotions that are not principally the result of flawed parent/child habits. She may well display some sensory integration problems, and she should be evaluated by a pediatric occupational therapist. Also, she may display some biologically-based emotional disorder, and the child psychologist can help you with the evaluation of this. Of course you are not going to look immediately at medication as part of the solution, but don't be stubborn about this. In many instances, medication can be a great benefit. You want to be sure that the diagnosis is correct and, if a biologically-based emotional disorder is present, then medication may be a useful part of the treatment plan. Two books you might like are Lynn Clark's SOS: Help for Parents, and Stanley Turecki's The Difficult Child. These will help you with the behavioral component of your daughter's situation.