I want to go to confession to confess an obivous sin but I do not feel remorse or regret for doing it. Do I need to be regretful to confess this sin or will it be forgiven even if I have no remorse?
Remorse and regret are emotions, which you may or may not feel and do not have control over. Repentance is an act of the will that one knows that one has committed sin and wills to reconcile with God. So long as you sincerely repent your sin, it is not necessary to have the emotions of remorse and regret in order to confess the sin.
However, although such feelings are not required, they are helpful because they encourage one not to commit the sin again. One way of developing such feelings over one’s sins is a suggestion my confessor gave to me the last time I went to confession: If you wish, consider spending a few minutes each day contemplating a crucifix. (The crucifix attached to a rosary will do.) Meditate on what Christ suffered and on how that suffering paid the price for the grace you receive through the sacraments (such as confession and the Eucharist). Developing a devotion to Christ’s Passion is a helpful means of developing a horror for sin and remorse for the sins of one’s life.