i am assuming you are older than 4?
how was your right arm twisted behind your back? and why did the doctor prescribe antibiotics?
It sounds like you have a ligament injury in your shoulder, could be the rotator cuff or something called a labrum tear. You need to see an orthopedic doctor. In the interim, buy soem Icy-Hot patches from the pharmacy, it may give you some temporary relief. You could also have injury to the nerve bundle called the brachial plexus. Either way, if you can afford it, I would see an orthopedic surgeon. He/she may be able to give you a cortisone shot for the pain.
I would discuss this with their office manager. I really cannot comment since I was not there. Of course when we think of chest pain extending down the arm, the first thing that comes to mind is a heart attack, however, given the history of trauma, I would have looked into other diagnoses as well. But that's just me. Doctors are not perfect and can misdiagnose from time to time, and please don't think I am sticking up for that doctor as I'm not, it's just not a situation I can comment on. Truly if you had proof of another diagnosis, such as records from an orthopedic doctor, I would bring it to them and see if they would waive or lessen the fees they charged you.
Best of luck,