My Doctor Is Forcing Me To Go To A Certain Pharmacy

Is it illegal for a doctor to force you to use a a specific pharmacy? One that is connected to there office also. They just built a plaza where everything is in one place. Doctors, lab corp, pharmacy in one plaza. So I switched doctors offices today. I had asked my doctor several times if I could continue to use my pharmacy that I've been using for the last decade. Today I was flat out told NO! I have to use thier pharmacy. I know I have a right to choose but I also feel because we have very few doctors in the specialty I am seeing them for that they feel they can force you to do what they say because they know there's noone else to go to in our region. But can I report this? And how? I'm in WV.