If one has not confessed what may possibly be a sin, then, yes, one has an obligation to “try and sort it out” in an examination of conscience before Confession.
If one has already confessed what may or may not be a sin, and has received absolution, then no, one should not thereafter try to sort it out. That’s whipping a dead horse, as it were.
One might do well to avoid asking a priest if something one is confessing is a sin or not. That will often only confuse you. When in doubt, I find it best just to presume it is a sin, confess it, get absolved, and then Totally Forget About It. It is gone! Gone in the sight of God, gone in the sight of the Church, and therefore it should be gone in the sight of me, also.