You had been captured and almost killed by the Phantom Troupe. They found out you were close with the Chain User, so they decided if they couldn't kill him, they'd take someone he cared about. Luckily, you were saved just in time, and Kurapika has taken a break from his mission to retrieve his clan's eyes and prioritizing your safety, he can't lose you too. And his way of doing it was to simply never let you leave his line of sight.