1) Jesus died to forgive our sins.
Jesus suffered and died FOR the sins of the believers. Past present and future. Forgiveness in a general sense, yes, but also as self-punishment. So God would not punish us anymore in this temporal life. No more Sodom and Gomorrah fire and brimstone. You are still accountable for your personal sin. The difference is, that now, with God's offering of sanctifying grace, a contrite heart, and by loving God above all, and your neighbor as yourself, you may have eternal life with God.
4) The pastor forgives my sins.
Actually, the Priest is acting "in persona Christi" (In the person of Christ. It is Christ who forgives you, (absolves you) of your sin. This is if you are truly sorry, and have a sincere amendment to avoid the near occasion of sin. To not sin again. The sin is forgiven, (it is no longer an impediment to entering eternal life), but the temporal effects of sin remain until the performance of penance.
5) Communion offers forgiveness.
There are other things too which you haven't even mentioned, such as the general confession in the Mass. Selfless giving to others. etc.
Communion offers sanctifying grace. It is our spiritual food. Strength for the journey. If the body and blood are properly discerned in the appearance of the bread and wine, then you are receiving grace from God. Here again. Not exactly forgiveness for your individual sin.
Baptism joins us with Christ's death. We die with Christ in Baptism, and are reborn with Him. Our original sin is no more. We have also been joined to the Christian community.
We still have a sinful nature. Jesus instituted sacraments to offer His grace to us as we live out our lives. Our small, or venial sins which are straying from the Christian path, are in fact taken care of in some of the ways which you have mentioned here. The Lord's prayer. The general confession of the mass. The atonement at Calvary.
Mortal sin is sin in which you have intentionally turned away from God. It is a deep wound, and even a severance from God's grace, by your choice. If you are truly sorrowful about mortal sin, and are willing to make it right, He offers personal individual forgiveness to the sinner in the sacrament of reconciliation, as an extension of the apostolic gift to bind and loose. When this occurs, you will be given absolution, THROUGH the Priest BY Christ. Performance of your prescribed penance will dispel temporal effect/punishment due to sin. Then, with the mortal sin cleared from your soul, and your sincere desire to resume your relationship with God, you are offered the sacrament of the Holy Eucharist, which is God's grace for strength in turning away from your sinful nature, and to be in "communion" with the entire mystical body of Christ, the Angels, and the Saints. To worship with them in thanksgiving (eukarista) in Heaven. Heaven and Earth touch at the point of communion. At the Holy Mass.
These are not all forgiveness for one sin, one time. They are a program, if you will, designed by Jesus Christ in order to keep you with Himself during your mortal life, so that you can be with Him eternally in the life to come.
I hope I am explaining this with charity, and with some kind of clarity. I'm not the most articulate poster on the block.