well I'm dealing with it since 14 (11 years now).... I can remember I felt it earlier, but wasn't that bad. it always comes with physical pain... and strongly connected to my depression/depressive reactions and ocd....
it got me into self harm when I was a teenager... it clouded my mind and let me get into trouble a thousand times (been abused an was too afraid to leave and than ran into an abusive relationship).... I always thought it was kind of "blues"; tried to benefit from it as an artist, but I was still bounded with people who previously abused me... it started yet again, and when I left that place I lost too much good things with it and I collapsed.... than I used alcohol and weed to reliese myself; but as I realised what is going on I stopped. Now I'm here; my mind is all naked....since than it is just my life.... it got more severe and more painful than ever.
It has periods, ofcourse when I'm alright, even happy and for a short time I can be careless aswell.... but the last good period was something like a year ago......