My dog has never howled before?

but these past few days he has been howling like a wolf a few times in a row last nite he sat in front of the livin room do lookin out at the hallway then today he is sat on hte stairs doing it,,he normally sleeps in the day but he wont seattle he jus is walkin around like a lost lil soul,,he is always makin this lil sad whine noise,,he has loads of company ,,constant attention gets takin out loads,,n hes 4 now i jus dont no y suddenly since last week he has been acting like this,,its makin me sad coz i dont no wats wrongwith him,,pls someone know,xo