How do I know if tinnitus is some sort of a placebo effect?

What if I am just imagining the high pitch sound in my mind whenever I hear about or think of tinnitus just like how someone tells you to imagine a whale and you form a mental image of a whale? I don't pay attention to the noise while I'm busy doing stuff but once I think about it, it is as hard to stop noticing it similar to being told to breathe manually, and it gets very annoying after some time. Is it what tinnitus really is?