What do the breasts represent?
Refer to 4:5:1:1-4.
Malbim (Melitzah): After describing the lack that will befall the lower part, the Kelim of Nefesh ha'Tzomachas, via death, it discusses what will befall the Kelim of Nefesh Chiyunis, which are from the chest to the head. They breasts represent the powers of desire and of anger.
Malbim (Mashal): They are like harts only in place of desire and beauty - in rooms of the king's ornaments, but not in the shepherd's house.
What is the significance of twin harts born to a deer?
Refer to 4:5:2:1-2 and the notes there.
Seforno: They constantly fight. (So the Nasi and Av Beis Din argued about Semichah on a Korban on Yom Tov.) Yosi ben Yo'ezer says that we are Somech; Yosi ben Yochanan disagrees (Chagigah 17a). Even so, the Tikun is possible if all of you will be in Eretz Yisrael, The Shechinah will dwell on you.
Malbim (Melitzah): The powers of desire and of anger are like two harts in the physical world. Then, desire is aroused for the beautiful, and anger is aroused to envy and vengeance, but not after death.
