Possible meaning are 1) "angel who represents Yahweh" or 2) "messenger who serves Yahweh" or 3) it may refer to Yahweh himself, who looked like an angel as he talked to a person. Either one of these meanings would explain the angel's use of "I" as if Yahweh himself were talking.
This is what the Israelites named this place in 2:5 after the angel rebukes the people. "Bokim" means "crying." (See: [[rc://en/ta/man/translate/translate-names]])
It is understood that the angel of Yahweh is speaking to the people of Israel. AT: "and said to the people of Israel" (See: [[rc://en/ta/man/translate/figs-ellipsis]])
This question is asked to cause the people of Israel to realize they have disobeyed Yahweh and will suffer because of it. AT: "You have done a terrible thing." (See: [[rc://en/ta/man/translate/figs-rquestion]])