Authorities said they were worried about her children's safety.
"(They said) I need you to come outside because you're putting your child in danger with the loud music," mother Megan Christopherson remembered, saying she was shocked and scared when a Chula Vista Police Officer ordered her and her daughters to move out of the pit area as Brad Paisley began playing.
Christopherson says she was singled out for breast-feeding four-month-old Gracie, who was strapped to her chest.
A woman from elite security approached her before she was confronted by the officer, Christopherson said in an interview on Saturday.
"She said that there were complaints about me and that I needed to stop. So I said I'll stop when my baby's done nursing," Christopherson said.
The law says women can breast-feed anywhere in public that mothers are allowed to be.
Chula Vista police say the officer asked the mom to move her baby and her 8-year old daughter to different seats for the baby's own good.
"The child doesn't have hearing protection on. The crowd is going to surge forward. Where you're at you're gonna get crushed. So we're afraid of your child getting crushed and we're afraid of your child's ear drums being hurt," Christopherson remembered the officer telling her.
"It completely was a cop-out. They're trying to cover this up because they know they legally can't remove me for nursing," said Christopherson. "I'm shocked. I'm disgusted at our society that women are shamed into nursing in bathrooms or their cars, or feeding their baby a bottle only because they're scared to nurse in public."
Christopherson says she's not done taking her daughters to concerts.