One of the things lost in most modern education is a rich and analytic set of tools for describing figurative language and figures of speech. A symptom of this can be seen, for instance, when people pit 'figurative' against 'literal' where they mean 'literal = taking it to be true' and 'figurative = it's not true just airy fairy'.
Figures of speech are endemic to language, you can't get away from them. Indeed, 'endemic' and 'get away from them' in the last sentence are figures of speech. Understanding that the way we construct and construe meaning relies on a vast array of different modes and figures of speech helps to clear some of the air to allow breathing space and say, "Hey, you know what? The Song of Songs can have figurative meanings".
That's what these preliminary comments are meant to do, because there's been a recent, but long-standing in recent terms, move to reject figurative readings, e.g. the allegorical reading that the love-poem is primarily about Christ and the Church. Most people who reject allegory (a) don't have a good grasp of what allegory is, (b) are familiar with some fairly wild and untethered allegories, (c) pin all the blame on the early church while having barely read any early church authors.
Now that I've got that off my chest, I think the Song of Songs admits, and invites, reading it at, at least, two levels. Firstly, it is a straightforward love story with overt sexual imagery. And so even at this level, you are reading a lot of metaphorical language because it's not explicit sexual imagery, it's flowers and fruits and so forth. Secondly, though, if we read the story both in a post-exilic setting, and in a canonical setting shaped by the metaphor of the divine marriage of YHWH and Israel found in the prophetic literature, it's hard to escape the idea that this love story too speaks to the love triangle between YHWH, Israel, and Solomon as the symbol of Hellenism.
Athas puts it well when he writes: “The Song’s meaning is about human love, sexuality, power, personhood, monogamy, and polygamy. The Song’s significance is about the struggle of Judaism to retain its orthodox, biblical principles and hopes…”1
I think this is right, precisely because the canonical shape of primary romantic relationship is used throughout to speak of God and his people, and in the New Testament that does become Christ and his Church (Ephesians 5). I really appreciate Old Testament scholars, especially when they get idiosyncratic and develop a penchant for refusing to connect things to the New Testament, blithely and bravely keeping things in an OT framework. And yet, the sweep of redemptive history brings you back to Song of Songs to read its significance in a figurative sense both then for post-exilic Jews under Hellenism, and now for new covenant believers.
In their case, then, we are again cheering on the 'true' romance between the male lead, YHWH, and his intended and destined bride, the Woman; and we scorn the interpolation of Solomon, who because of his associations speaks strongly to the pressures of Hellenism, syncretism, and the kings of other nations. Those pressures were real, and became fatal for faithful Jews. In that sense, it truly became a matter of fidelity unto love, at the cost of one's life. The same thing we see in the final chapter of the Song.
In the light of the New Testament, we take the male lead to be Jesus Christ, and his bride is still God's people, seen as the church; not the gentile church alone though! not the church in contrast to Israel; but the church as enveloping all God's people. Solomon, as threat, becomes perhaps more abstract or more concrete at various times and places; but always there is both lure and pressure to give up one's true love, and the real threat of death for love's sake (in some times and places).
Love that is stronger than death is also love that is willing to suffer death, and that is true of both sides of the romance between God and his people, nowhere and nowhen more clearly than the cross. For there, of course, it is the love that endures death for the beloved's sake, that not only proves his love, but redeems his beloved, and overcomes death itself. His love, then, calls forth our love unto death in return.
Athas p, 263.