-- Andrea Cao is still in high school but she may have given her mom the best gift of all: the ability to quit her job.
This story begins four years ago when Hong Cao would come home from working 12-hour shifts as a hospital nurse tired and aching. Cao said she would ask her daughter Andrea, now 14, to rub her back.
"She was tired of doing what I asked her to do," Cao told ABC News. "Initially, she said, 'Why don’t you do it yourself.' I said, 'How can I touch my back?'"
Andrea told her mother she was determined to find a solution.
Cao said she brushed it off but soon the two became serious, fiddling with various materials, including PVC pipes, wood, metal and various plastics to create a contraption with a hook shape.
After settling on a mold, "we opened the phone book and found a manufacturer and made a first order of 20," Andrea said.
"I went door to door selling them -- anywhere I could: my church, my school. I was dealing them out of my backpack," she said. "My mom thought I was crazy."
Cao used the product they would later name the Q-Flex, but Andrea had even bigger ambitions to grow their business. She asked her mother if they could audition for ABC's hit TV show "Shark Tank."
"I dragged her to the open call, wrote up the pitch myself. We went through the rounds and made it to the show," Andrea said.
Sales skyrocketed after the show aired -- and with that the mother-daughter duo had to make even bigger decisions together as equal business partners.
"We have a lot of disagreements but we try to solve them in a peaceful way," Cao said with a laugh.
One example: After the show aired, they offered free shipping for the entire month on Q-Flex orders.
"I disagreed with that," Andrea said, "But my mom and Barbara wanted to do it. In the end obviously my mom won but that's OK. We got over it."
Amazon Exclusives, the a new digital storefront that seeks to bring up-and-coming brands, partnered with the mother-daughter duo earlier this year, helping them to attract new customers and fulfill a growing pile of orders.
After putting an order form in the teacher's lounge, Andrea said she racked up around $1,000 in sales.
"Basically any free time I have in class, I check emails, do customer service, take care of PR," Andrea said.
As for her mother, she was able to quit her job in March and enjoy newfound flexibility in her work days -- all thanks to a common problem Andrea helped solve.
"It's amazing working with my mom," Andrea said. "She does so much and is my inspiration."