Kristopher83 can I suggest that you have a look at the thread on Labarynthitis
http://www.pprune.org/forums/showthread.php?t=229150
as the symptoms that you described are exactly what I had.
It may well be that you have Otitis Media with Effusion (middle ear infection) and the crackling that you hear is the fluid behind the eardrum.
Get this checked with your GP and if available, get referred to an ENT surgeon who will be able to check whether you really do have fluid in the middle ear by using a pressure testing device.
Luckily, my ear has totally healed but there is a nasty virus doing the rounds. I would also suggest not flying until you are given the all clear as you might well cause yourself vertigo if you do so.