What does Acts 22:11 mean?

Paul is explaining to a murderous mob why he was seen in Jerusalem with a Gentile.

When he was young, Paul trained under the rabbi Gamaliel to become a Pharisee. He so devoted himself to the Mosaic law that he approved of Stephen's murder (Acts 7:54–60; 22:20). He then hunted Jewish Jesus-followers to bring them to court where he voted for their executions (Acts 8:1–3; 9:1–2; 26:10). On the way to Damascus to hunt Jesus-followers, Paul met Jesus in a literally blinding light. Jesus accused Paul of persecuting not His followers, but Himself. Jesus then told Paul to go to Damascus and wait for His messenger. When Ananias arrived, Paul was still blind, but when Ananias laid his hands on Paul, scales fell from his eyes, and he could see again (Acts 9:3–19).

In 2 Corinthians 12:7, Paul writes, "So to keep me from becoming conceited because of the surpassing greatness of the revelations, a thorn was given me in the flesh, a messenger of Satan to harass me, to keep me from becoming conceited." It's not sure what this "thorn" is—or even if it's physical or spiritual. Some think Paul never fully recovered his sight. Others think Paul's thorn was a sinful temptation. The day after Paul's speech here, he will present his case before the Sanhedrin and accidentally call the high priest a "whitewashed wall" (Acts 23:3). It's possible Paul does so because he can't see who is before him.

Paul goes on to explain that he eventually returned to Jerusalem, where his conversion and aggressive evangelism style led former allies to try to kill him. God sent him away from Jerusalem and told him to spread His story among the Gentiles. While doing that, Paul met Trophimus, who came to Jerusalem with support from his church for the poor believers living in Jerusalem (Romans 15:26; Acts 20:4). This is why Paul and Trophimus were in Jerusalem together.