It is clear from verses such as the following that one title for Jesus is “Son of God.”

Matthew 8:29
And suddenly they cried out, saying, “What have we to do with You, Jesus, You Son of God? Have You come here to torment us before the time?”

Matthew 14:33
Then those who were in the boat came and worshiped Him, saying, “Truly You are the Son of God.”

Matthew 26:62–64
And the high priest arose and said to Him, “Do You answer nothing? What is it these men testify against You?” But Jesus kept silent. And the high priest answered and said to Him, “I put You under oath by the living God: Tell us if You are the Christ, the Son of God!” Jesus said to him, “It is as you said. Nevertheless, I say to you, hereafter you will see the Son of Man sitting at the right hand of the Power, and coming on the clouds of heaven.”

Mark 1:1
The beginning of the gospel of Jesus Christ, the Son of God.

Throughout Scripture, others are also called “son(s) of God.”

• Adam (Luke 3:38)
• Angels (Job 1:6, 2:1, 38:7)¹
• Believers (Matthew 5:9; Romans 8:14, 19; Galatians 3:26)

“A son of God” or “sons of God” are monikers for those who follow after God. But the phrase “the Son of God” is used only for Jesus Christ. He is called the “only begotten Son” (John 1:14, 3:16, 3:18; 1 John 4:9) and “His [God’s] own Son” (Romans 8:3). Jesus is referred to as “the Son” when God is referred to as “the Father” (John 3:35–¬36; 5:19–27; 6:40; 17:1; 2 John 1:9; Matthew 28:19). In fact, Jesus is the Son, the second person of the Godhead, which cannot be said of any human or angel.

When understood from the whole context of Scripture, there is really no contradiction. Jesus is called “the only begotten” as the unique Son of God in a very real sense that no angelic being or member of humanity can share.