Rashi: There can be many explanations of one verse. The verse does not leave its simple meaning. Shlomo saw with Ru'ach ha'Kodesh that Yisrael will be exiled multiple times; there will be Churbanos. Yisrael will mourn over their former honor and dearness. They were Hashem's Segulah from all nations! They will want to return to their first 'Husband', for then was better than now. They will recall His Chasadim and their transgression, and what He promised to give to them at the end of days. Shlomo composed this with Ru'ach ha'Kodesh to depict a woman who longs for her husband. She recalls the love of her youth and admits to her sin. Her beloved is pained due to her pain. He remembers the Chesed of her youth, beauty and proper deeds. Through them, he is tied to her with a strong love. This informs Yisrael that they were not divorced; she is still His wife, and He is her husband, and He will return to her.

Malbim (Melitzah): This Shir is divided into five ¹ . It discusses the Yetzer of Shlomo's body that loved a Rayah, a daughter of Shamayim - the spiritual Divine Neshamah that is trapped in his body, the place of the Yetzer's kingship and authority. [The Yetzer] put Bnos Yerushalayim, i.e. the various physical powers, guarding around it, to immerse it in physicality and draw it to [the Yetzer's] desire to be its concubine. However, [the Rayah] is tied with thick ropes of love to its Beloved in Shamayim, who shepherds the legions that He created. Five times [the Rayah] left the body, which is the palace of the Yetzer that rules there, and joined with its Beloved in Shamayim ² . The first four times were when Shlomo was alive. These were via a Divine Ru'ach of Divine visions. Each time it returned to the body when the vision ended, when Bnos Yerushalayim (physical powers) woke from their sleep. The fifth time that it separated from the body was when Shlomo died. It clung to its G-d in the bind of eternal life. Each Shir describes how it left physicality and clung to its Beloved.

Rashi: It is above all that Hashem's congregation and nation, Keneses Yisrael, said to Him. The greatest day was the day that Shir ha'Shirim was given. All Kisvei ha'Kodesh are Kadosh, and Shir ha'Shirim is Kodesh Kodoshim. It is all Yir'as Shamayim and accepting Ol Malchus Shamayim.

Seforno: All Shirim are Kadosh, and Shir ha'Shirim is Kodesh Kodoshim. I.e. among those that Shlomo said - "Shiro Chamishah va'Alef" (Melachim I, 5:12). All were Kadosh in which Yisrael rejoices in their Maker. This Shir is to prepare man's heart, especially one who suffers mishaps. One who knows His goodness will surely love Him - "Shma Yisrael Hashem Elokeinu Hashem Echad; v'Ahavta

Torah Temimah citing Sanhedrin 101a: No! If one does so, or reads verses in the pub out of place (just for fun), he brings evil to the world. The Torah girds itself in sackcloth and complains to Hashem 'Yisrael treat me like a harp for scoffers to play'!

Rashi citing Shevu'os 35b: [Almost] every 'Shlomo' in Shir ha'Shirim refers to Hashem (the Owner (or Maker) of Shalom). Some exclude "ha'Elef Lecha Shlomo ¹ " (8:12).

Seforno: Shlomo ha'Melech wrote this about ha'Melech ha'Kadosh, that Shalom is His and from Him. When He hides His face there is loss - "Tastir Panecha Yibahelun" (Tehilim 104:29).

Malbim: Yes, i.e. the Yetzer and power of arousal of his body. Refer to 1:1:1:3.