In his Lettres écrites de la montagne, Rousseau writes this:
It's all very well to confuse independence with freedom. The two things are so different that they are even mutually exclusive. When people do as they please, they often do what others do not like, and that is not called a free state. Freedom consists not so much in doing one's own will as in not being subject to the will of others; it also consists in not subjecting the will of others to our own. Whoever is master cannot be free, and to reign is to obey. [...] I know of no will that is truly free except that which no one has the right to resist; in common freedom no one has the right to do what the freedom of another forbids him to do, and true freedom is never self-destructive. Thus freedom without justice is a real contradiction; for however one goes about it, everything hinders the execution of a disordered will. There is therefore no freedom without laws, nor where someone is above the law: in the very state of nature man is free only because of the natural law that commands all. A free people obeys, but it does not serve; it has leaders, not masters; it obeys the laws, but it obeys only the laws, and it is by the force of the laws that it does not obey men.
My question is, according to Rousseau, why am I not free if I am subject to another? Why am I not freer if I am the master?