In English, "you" is valid for both plural and sigular.
You all is used only in specific regions.
"Did you hurt yourself" is a good translation in singular (yourselves in plural). But this suggests that the person did it on purpose, instead of an accident. While "Did you get hurt" suggests it was not on purpose. The Portuguese sentence can be used for both meanings.
Danmoller is right in that "you all" is regional and not used throughout the USA, and not used at all in other English speaking countries. But, in Texas "you all" is singular, "all you all" is plural. I'm not kidding! We have relatives in Texas that we visit on a regular basis.
There are two meanings for "Were you hurt".
One is "did you get hurt?" = "Vocês se machucaram?"
In this case: "were you hurt" = "vocês foram machucados?"
"Did they hurt you?" = "Machucaram vocês?"
Another is "were you hurt" not as the action of getting hurt, but as the state of being hurt, like in "were you not good?".
In this case: "Were you hurt" = "Vocês estavam machucados?"