Refused medical treatment because I'm legally smoking

I live in the USA - a place that is supposed to be chock full of personal rights, privilages and freedoms. More specifically, I live in a state that voted to make medical marijuna legal. I have always been under the assumption that people here also have the legal right to recieve medical treatment.

My doctor sent me to a pain management clinic where I was refused treatment soley becuase I legally smoke marijuana. I have a permit to grow, transport and consume. Is this legal because it is a business that can reserve the right to refuse service to anyone? Or is it illegal? I thought the health care industry was not allowed to refuse service, even for things as important as not having enough money.

Any thoughts?