Though being discontented because of something is never wrong, discontentment in and of itself does not cure one of the cause of the discontentment. Without the ability to cure oneself of the poor circumstance causing the sorrow, one becomes subject to hopelessness. Despair is never good; in the words of Issac Brock, "Self-pity me, it's so pitiful." How does one gain the right to voice their opinion? In America, the right to free speech is in our blood. It is rather one's ability to analyze problems that will make the world a better place.
Therefore I say, speak of your own opinions with fearlessness. No one can deny you of your feelings. However, personal experiences alone will not do well against all authorities. In the words of Martin Luther King Junior,
We know through painful experience that freedom is never voluntarily given by the oppressor; it must be demanded by the oppressed.One must learn how to express one's feelings in such a way that would be considered reasonable. Do not simply complain about a broken system for it is one thing to see a bad thing and recognize it as a bad thing but it is another to understand what makes it bad. The understanding of the problem will lead to a cure. In this way, I prompt you to consider the problems of humanity and of whatever you are dealing with. Find a cure that makes sense. One in which everyone wins.
I wish you the best of luck on your quest to make the world an awesomer place to live.