I’m a pilot suffering from a weird left ear pressure?

I am a 28 years old male suffering from weird left ear pressure from 6 months ago, I am a healthy airline pilot. My sypmtoms are mild ear pressure only in the left ear. No pain and hearing is fine. I went to the ENT who checked my ears and said it is normal and asked me to do pressure test (cause I am a pilot) which became normal too! He ruled out any ear infection and said it might be TMJ. I looked out TMJ symptoms on internet and found it is not applicable with mine because TMJ = pain (specially when closing opening jaw). Honestly I dont feel any pain around my jaw, But when I open/close my jaw I can feel a cracking sound in the left jaw (yes around my left ear) but still no pain. The pressure I feel is comes very quickly either when I rest the back of my head on the chair or when I lay the back of my head on bed. Also this discomfort is very noticable when I close my eyes! Sometimes the valsava manuveur makes me feel better only for a few seconds.

Also I was diagnosed with thyrioditis few months ago and it became normal after few months of observation, local ENT said it had nothing to do with my left ear.