Question abt African Grey..

My African Grey keep making a noise tat sound like blowing nose..not sneezing but like clearing his nostril..n he like to go to a corner of his cage to dig..its like a dog diggin the ground to try n bury his bone..its been like tat since i first got him abt a mth plus ago,n i had brought him to the vet..his discharge r normal,no liquid comin out of his nostril,eatin well..was told tat it could b a habit or attention seekin moves n tat he pick it up b4 my purchase..m doin my bit not to respond to him,hopeful he will kick the habits..any bro come across such incidents??