lindbergh said it best, you don't know how to fly until you have taught someone else how to fly.
so there you go, when you feel you could teach someone else how to fly, you may very well hear the clicking sound.
but if it is from your teeth, see a dentist.
you should be consciously thinking about everything, though I would say altitude and not height...maybe it is a british thing.
a friend told me you are not a real instrument pilot until you can fly an approach to minimums while eating a hamburger.
so, 28 hours...be patient little bird.