"It was horrible, because even when you're lying in bed you can't get comfortable," said Phillips. "I tried to take my girlfriend on a date during Idol and we got maybe 20 steps and I was like, 'I can't make it.'"
The 22-year-old is feeling much better now, having recently undergone a six-hour surgery to rectify the problem, but earlier this spring he was forced to cancel several headlining tour dates due to doctor's orders. Those dates have since been rescheduled for fall.
Fans can also catch Phillips on tour this summer, opening for John Mayer.
"John is an awesome guy," Phillips raved. "Right off the bat -- the first show -- he invited me up to his dressing room and said, 'Hey, what's up? I'm excited to have you.'"
Phillips is also a fan of Mayer's on-again girlfriend Kate Perry.
"She's just a cool person," said Phillips.
Phillips' single, Home, has sold more copies than any other American Idol alum, while his new single Gone, Gone, Gone has already gone platinum. Both songs are featured on his debut album The World from the Side of the Moon, available now.