When Solomon speaks of crookedness, he is not specifically speaking about sin. In fact, some crookedness is actually good, because it is created by God (Ecclesiastes 7:13)! But in general, sin and crookedness overlap in many ways because, when one person is wrenching something from another, whether physically or metaphorically, sin is almost always involved. It is the “way of get”; it is an act of self-centeredness.
On a human level, the crookedness in the world began in the Garden of Eden, when Adam upset the order of things by heeding the voice of Eve rather than the voice of God. He made a choice, and that choice introduced crookedness into the relationship between God and man. What Adam made crooked could not be made straight by any subsequent human action.
In fact, the more people there were, the more crooked the world became until finally God intervened by, not only drowning most of mankind, but also by shortening the human lifespan. In doing so, He dramatically reduced the amount of time during which any single person could make things crooked. Yet, even with only his allotted three-score and ten or perhaps four-score, each man has plenty of time to make things crooked in his and others' lives.
Crookedness began on a human level with Adam, yet it goes back even farther, to another being who was in the Garden (Ezekiel 28:13). The crookedness in God's creation began with a created being, Satan, whose heart was lifted up, who thought of himself more highly than he should. After his own heart and will became crooked, he began wresting the wills of other angels, then those of mankind. He is the source of this kosmos—this anti-God world—as well as human nature, and thus wherever those are found, we can also expect to find some crookedness.
What this means is that, even though God has redeemed us, any place in our lives that the world still holds sway, or any area where we allow human nature to get the upper hand, something will be made crooked. Our will will assert itself and be manifested in a perversion of justice, in wronging someone, in turning a matter upside down, in dealing deceitfully, or in upsetting the relationship with God by overlooking His will for us.