Job 7-8

If I sin, what do I do to you, you watcher of mankind? Why have you made me your mark? Why have I become a burden to you? 21Why do you not pardon my transgression and take away my iniquity? For now I shall lie in the earth; you will seek me, but I shall not be.

-- Job 7:20-21

Is there a struggle in Job's thinking? He seems to be aware that he is perfect with God by asking "If I sin ...", but then asks in v21, what was the transgression that could not be pardoned? How could there be transgression and perfectness? In Romans 3, weren't we told that no one was righteous except Jesus? Where does Job fit in?