Hi Dyin2Live,
Now our Lord Jesus Christ has forgiven your past sins when you are saved, when you pray the Sinner's Prayer of Salvation. Sadly, there are many distorted versions of this prayer, which has been contaminated by the new "new age" thinking and gospel that is being taught these days.
When a past sin keeps on coming to mind, I would say that it is being brought to your attention because there is still something hanging onto to your sins, such as unforgiveness.
You may have committed a sin, which may have affected other people. And you need to ask for their forgiveness. Forgiveness is a two-way thing, and a lot deeper than most Christians are led to believe by fairy-floss beliefs.
My ministry is FORGIVENESS, and I can assure that forgiveness is a lot deeper that what most like to believe.
Many tend to forget the enemy, and what rights he may still have on a person who had committed sins before being saved.
Yes, every time you mess up, then you have to confess, repent, renounce, and rebuke the enemy of your mess up, that is, SIN. SIN needs forgiveness in two different directions. Forgiveness from our Lord Jesus Christ, and forgiveness to or from the people involved in the SIN.
Now LOVE, is another part of forgiveness. You may forgive a person, but do you love them? Well it doesn't work that way at all. With forgiveness comes love!
If you have some real serious issues you wish to talk about then PM me, and I will give you some sound advice on forgiveness.
Love in Christ