“and stopped.” God had moved to the threshold of the Temple and gave the command to destroy Jerusalem (Ezek. 9:3-7). Then He got back on His chariot-throne and moved to the east gate of the Temple (Ezek. 10:18-19). From over the east gate, He moved to over the Mount of Olives (Ezek. 11:22-23). God and His glory will not return to a Temple in Jerusalem until the Millennial Temple (Ezek. 43:1-4). So the continual sin of Judah, and their hardheartedness, drove God away. God, surrounded by His glory, left Judah and Jerusalem, which were then destroyed by the Babylonians. In Ezekiel’s vision this is as far east as the glory of Yahweh traveled, although it seems clear from Ezekiel 43:2 that it had eventually left Judah and traveled east. [For more on Ezekiel 8-11 and what happened, see commentary on Ezek. 8:4].
“the mountain that is on the east side.” That mountain is the Mount of Olives.