The Dirty Dancing star, who underwent surgery last year for injuries sustained while appearing on Dancing with the Stars, has suffered with pain ever since a car wreck in 1987.
Grey has since launched Partners Against Pain, a national education programme geared towards improving pain management for sufferers and encouraging a hands-on treatment approach.
"I have been suffering for so long and didn't even recognise it. I just stopped doing so many things that I used to love to do due to my pain," Grey explained to Parade.
"There are millions of Americans who are suffering from chronic pain. I really believe that we're all in this together. I don't feel any shame about it. It just happened. You get injured, you get older, and you do Dancing with the Stars!"
It was recently announced that Grey will appear as a guest judge on BBC One's Strictly Come Dancing, filling in for panellist Len Goodman.