Few people know Paisley Park – Prince’s creative sanctuary – better than Kirk Johnson, a drummer for the artist and the best man at his first wedding.

It’s where the music legend lived, performed and passed.

“Do you get chills sometimes when you walk around?” CBS News’ Jamie Yuccas asked.

“I’ve been here 30 years. I mean it’s the energy. It’s not necessarily chills, but it’s the energy,” Johnson said, in an interview you’ll see only on “CBS This Morning.”

Johnson, who was one of Prince’s closest confidants and was with the music icon during his tumultuous last week, is still mourning the loss of his friend.

“People have so many questions about Prince’s last days and you know—” Yuccas said.

“Kirk has a vault. Right here. It’s never gonna be unlocked,” Johnson said, pointing to his head.

“Is that because Prince was so private?” Yuccas asked.

“I respect him and, you know, what his privacy was,” Johnson said.

Johnson was reluctant to talk about the past, wanting instead to honor Prince’s legacy.

Kirk Johnson CBS News

Johnson showed us various exhibits around Paisley Park, including where Prince was working before he died, and a rarely-seen concert venue, a tribute to his 2007 Super Bowl performance.

The notes and cards left outside Paisley Park are now on display inside.

Prince, a genre-defying icon, sold over 100 million records worldwide. The phenom was known for his relentless vigor and demanding performances.

“Did that eventually wear him out?” Yuccas asked.

“Well, I mean, you know, you get tired after a while,” Johnson said, chuckling.

It’s that dancing that reportedly prompted Prince to turn to painkillers. Prince Rogers Nelson died on April 21, 2016 from an accidental overdose of fentanyl, a type of opiate.

“Was he hurting?” Yuccas asked.

“I don’t know,” Johnson said. “We danced a lot. I mean, I feel the effects of dancing. You know, your joints get, you know, hurt.”

“Well, and he was very vigorous at that,” Yuccas pointed out.

“Yeah, he was a non-stopper,” Johnson said.

Johnson was on a fateful flight with Prince, when it made an emergency landing in Illinois. Prince was revived with a shot of Naloxone, which is used to treat opioid overdoses. A week later, Johnson was among those who discovered Prince dead inside an elevator.

Prince’s final days remain a mystery, even to family members like Prince’s cousin, Chazz Smith, who demanded justice when he spoke to Yuccas last June.

“Is the family mad at anybody?” Yuccas had asked.

“Yeah, we’re mad! Yeah, we’re mad! Somebody had to know that he was suffering like that and, to me, if you loved him enough, you would think and you would have fought,” Smith had responded.

While the investigation into Prince’s death continues, preparations are underway for a four-day celebration of his life.

“There are a number of people who say, ‘They shouldn’t be opening Paisley Park. You know, they’re profiting off of Prince’s death,’” Yuccas said.

“Yep. I mean that’s normal,” Johnson said. “But … it’s supposed to be open to the world. He wants everyone to see what he’s created.”

The Carver County sheriff’s office in Minnesota is working with the U.S. Drug Enforcement Agency to determine where Prince got the opioids that killed him. They say the investigation is ongoing and that Johnson is part of that investigation. But they won’t reveal to what extent.