crackles when lying down during deep inhale

Over 15 months now have consistent and unique symptoms.
While inhaling only and only in the latter part of a deep breath a feeling of ronchi/crackles especially on left back side (but sometimes middle part of chest as well).
Also this occurs only when lying on my back or lying on my left side but never when lying chest down or standing stright upward.
Also, after a deep breath when feeling the ronchi sound it sort of clears it for the next 30 seconds or so i.e. a second consecutive immidiate deep breath will not result the sound (only if I wait 30 seconds or so).
Chest x-rays are normal.
Bronchoscopy of the lungs was performed and came out with no findings.
No coughing or breathing difficulty.
My specialist doctor does not have an idea and just wants me back in 6 months for a checkup.
Anyone can suggest or give a clue ?????
P.S. This hole thing started after an ilness which involved a lengthy and strong cough period of over a month.
Thanks

[natzf]

just to say your symptoms sound exactly like mine, and i've had this for over a year now, and am also asthmatic. Did you ever get an answer?