Are there any passages in Scripture that shows someone confessing their sins to an apostles and that apostle forgiving those specific sins?
In 2 Cor. 2:10, Paul states with respect to the incestuous man that whatever he [Paul] has forgiven, “forgave I it in the person of Christ.” (KJV) In chapter 5, Paul mentions being an ambassador of Christ. And he also says that Christ “hath committed unto us the word of reconciliation.” An ambassador serves with the powers of the King. The “word of reconciliation” in the sacramental sense, is the ability to pronounce absolution.
You have to be reading this with your Catholic goggles on to catch this and to understand it as a reference to the early appearance of the Apostolic power of absolution/reconciliation (just as you need those same liturgical goggles to understand that the Epistle to the Hebrews is ALL about the Eucharist!).
Where in John 20:22-23 do we see any evidence of a confessional or anything like you have in the catholic church?
The essential feature of Jn 20:22-23 has not changed: that Christ entrusted the Apostles with the power to forgive and retain sins the forgiveness of sins. Catholics believe this HAD to be transmitted to their successors as well because Christ would not leave His Church without an effective means of transmitting the central message of the Gospel until He comes again – namely, the forgiveness of sins.
The externals of the sacrament changed over the centuries, from open confession in front of the whole congregation in the early Church to private confession with a priest only (and aren’t we glad about THAT!). “Phone booth” confessionals were an innovation after the Council of Trent. And a good one, if you ask me.
My second question is: must a catholic confess his-her sins to a priest to be forgiven?
Yes. This is the normative way that Catholics receive absolution. In case of urgency, such as a ship going down and no priest available, a Catholic with perfect contrition, may be assured of the Lord’s forgiveness. However, if he makes it to shore, he must go to confession as soon as he can. Neither God nor the Catholic Church hold people to a duty they are unable to perform.
Confession is just about the BEST thing about being Catholic!