out of curiosity, does metal music always contain screaming? just curious.

No it doesnt. Look at bands such as Metallica, megadeth or anthrax or even powerwolf or WOLF. Wait?.... What is a Justin bieber tagahanga doing in the metal club? Im just wondering, I'm not a troll

metallica is heavy but has no screaming but u look at bands like system of a down and slipknot they r a bit of both screaming and heavy with no screaming but than u look at a band like tupa of god or burn the priest or cannibal corpse the are death/black metal so its just only screaming singing

Hell no.
There are enough metal genres without screaming :).