His grief is heavy — “the pain is excruciating” — but activist Ra Joy said he chose to run on Democrat Chris Kennedy’s gubernatorial ticket to turn his pain into “purpose.”

Kennedy officially announced Joy — the executive director for Change Illinois — as his running mate on Thursday. The non-partisan group most recently helped push for automatic voter registration, which Gov. Bruce Rauner recently signed into law. Joy issued his resignation from the advocacy group on Wednesday.

Joy’s 23-year-old son Xavier was gunned down in June in Woodlawn by someone trying to steal his cell phone. His son had chosen to do a year of service in his hometown, spending an AmeriCorp “City Year” on the South and West sides.

An emotional Joy said before losing his son, he would speak to him about “navigating the world as a young black man and where you can live and live free from fear and live with dignity.”

“He loved Chicago, and he worked on both the South and West sides of the city,” Joy, 44, said. “Part of me, I didn’t want him here. I did not want him here because the risk is just too much. And he wanted to be here.”

Joy said he’s spoken to many who have lost loved ones as he has dealt with his own grief.

“Physically the pain is excruciating,” Joy said. “I live in Bronzeville right next door to Dr. Daniel Hale Williams’ home. He performed the world’s first open heart surgery, and sometimes I think it would be easier for me to have my heart removed because [of] the grief.”

In speaking with other families who have lost others to violence, Joy said he became determined to do something about it.

“That pain, it’s like you drop a rock in a well, and you listen. It’s never going to hit the bottom. That is a bottomless pit of pain. And I am determined to do something about it,” Joy said. “First and foremost I can no longer live in Chicago and not do all that I can to fix what’s broken in our city.”

Kennedy, has of course, experienced his own share of grief, and he’s already laid out plans to try to target the city’s violence epidemic. The candidate is the son of Robert F. Kennedy, who was killed in 1968, and the nephew of President John F. Kennedy — assassinated in 1963.

Kennedy said he was considering Joy for the ticket as early as March, but after Xavier Joy’s death, Kennedy held off on his decision out of respect to the family.

Violence aside, Kennedy said he chose Joy as his running mate after speaking with a group of activists in a Bronzeville apartment who said they were so discouraged about President Donald Trump’s presidency that they didn’t plan to vote.

“I said ‘Oh my God.’ These millennials we’ve got to build back up the idea of public engagement. Sitting out, taking a pass that’s like you’re hurting yourself,” Kennedy said, adding he needed to send out a message that they can fight back.

“Here is the guy who embodies the entire message of this entire campaign, that we can change government, and because we can, we must,” Kennedy said of Joy.

Kennedy announced his pick in a video sent out to supporters.