This is a good question. From a broad perspective, the whole sonnet is figurative. From the surface it is hard to understand what is happening, but under closer examination, there are three main points, which are logically tied together. First, there is a given premise: beauty should multiply. Second, there is a problem: this person of beauty is self-absorbed and so does not want to multiply, because he is too preoccupied with himself. Third, there is an exhortation to procreate before time runs outs.
There is figurative language. Consider how Shakespeare describes the self-absorbed person. Rather than saying that a man is arrogant, Shakespeare says: he feds his light or flame with fuel. When he does this he creates a famine where there should be abundance. Wonderful imagery! All of these images are figurative.
But thou, contracted to thine own bright eyes, Feed’st thy light’st flame with self-substantial fuel, Making a famine where abundance lies, Thyself thy foe, to thy sweet self too cruel.
Shakespeare also says that this person is an ornament of the world. This is a metaphor of what his beauty is in the eyes of the world.
Thou that art now the world’s fresh ornament And only herald to the gaudy spring...
Almost every line has figurate language.