Macbook Pro was silent, now noisy

My MacBook Pro used to be silent when I first bought it in April and now doing the simplest things like using Chrome for browsing and using iTunes, the processor keeps making noise like my old (windows) laptop used to make.

Is it common to be silent for a couple of months and then turn noisy?

Nope nothing that I wasn't doing before.


It's no big deal I was just hoping that it would be quieter for longer.