Would you feel discriminated against if you were told? “You are on Medicare and you do not get a choice”

I went into a store to pick up a prescription and the Pharmacy Technician knew that I could only take this one type of medication and when he went to call the Doctors office to have it corrected the Pharmacist said that “he is on Medicare he does not have a choice” I felt as if I was a second class citizen and that I was being discriminated against. Was this wrong for me to feel this way?