originality of opinions

Opinions, unlike matter, CAN be created and/or destroyed. If this is true, then how much of my own thoughts do I have complete control over? Maybe feeling as if my outlook, my view, on something, anything really, is entirely original, my own, is ignorant. My opinions must have been created by another, but I am incapable of grasping that thought. If all opinions are formed by others, where did it all begin? Who else questioned this? Who was the first? Undoubtedly, every idea circulating in my brain had to be stimulated by something(others' discoveries, opinions, ideas, and/or facts). My mind is uncontrollable. Even my own responses are not completely up to me. Everything goes back to my opinions that were molded by others', so what is my own? What are MY thoughts?