Rick from Pawn Stars’ son, Adam Harrison, died on January 29. The cause of death has now been revealed a month after the shop owner paid tribute, on the same day Rick launched an app. Adam Harrison did not appear on Pawn Stars as a cast member but he did work in the store his father owned. At the time of Adam’s death, he was working as a plumber, but he usually kept out the public eye. Adam Harrison’s cause of death Harrison, 39, died of an accidental overdose of fentanyl and methamphetamine, the Clark County Coroners Office confirmed to TMZ. The 39-year-old died on 19 January in Las Vegas, Ne…