I'm afraid many people find it hard to admit when they've been wrong, especially when they have hurt someone (either by their actions or their words). But when we fail to apologize and ask that person's forgiveness, we only make the situation worse.
Why do you find it hard to say you are sorry and apologize for what you've done? There may be several reasons—but the most important is pride. You hate to admit you were wrong, and you hate to lose face in the eyes of other people. The Bible says, "Pride goes before destruction, a haughty spirit before a fall" (Proverbs 16:18).
How should you deal with this? First, realize just how damaging pride can be. Pride cuts us off from other people—and most of all it cuts us off from God. The Bible warns that "God opposes the proud" (James 4:6). Confess your pride—and all your sins—to God, and ask Jesus Christ to come into your life to forgive you and cleanse you. God loves you, and He doesn't want you to go through life hurting both others and yourself.
In addition, ask God to help you control your tongue, and to use it for His glory. Let the Bible's admonition be your guide: "Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen" (Ephesians 4:29).