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I agree with Ann that Acid reflux, GERD, could well be the reason for the licking.
He seems distressed and this is his way of showing it. The GERD would be more likely to appear early in the morning when his tummy is empty and the acid disturbs his stomach. As he is older and has trachea issues too, I would consider this. My dog has GERD and if he has not eaten for a long time he can throw up bile or white foam. I give him 1/4 of a 10 milligram of Pepcid with his last small meal at night and that stops the morning issues. You might want to try this once and see how it goes. As I am not a vet I am reluctant to suggest this, but it should not do any harm.
It could be other things as others have suggested so it would be wise to get a vet check him out.
Hope this resolves soon and the licking stops.