rattling sensation in ear

Hi guys,

I have a problem with my left ear that I hope you could provide some guidance on: At certain frequencies and intensities of sounds (and
this varies from day to day) I feel a sensation of physical rattling, in my ear. This has been happening on and off for the past 5 years (I'm 26). I saw an audiologist probably 4 years ago when it first bothered me and he said he didn't know what was causing it, and otherwise the ears were diagnosed as normal. Lately the problem has been getting much worse - sometimes I experience the rattling even when I speak loud enough; pubs or anywhere with moderate music set it off. Any ideas? It is particularly set off by high pitched noises. I dont think it's tinnitus, as my ringing is only due to real external sources of noise.

Thanks for any guidance or advice.