Samsung Vertical Colored Bar (1 Viewer)

Hey Everyone, I have a 50" Plasma Samsung PN50B650 TV. Four years old, but very little use. 4-5 hours per week max. A few months ago, I started getting this miscoloration on the right side of the screen. It's a vertical bar about two inches wide. It would come and go, flickering. The color changes. It got to the point where the miscoloration is permanent now. When theres no input (black screen), the bar tends to be solid green. When theres something being displayed, the bar flickers in color. I've attached a screen shot . Does anybody have any idea what could be causing this?

https://plus.google.com/photos/107279198486276596870/albums/5999239473407968129/5999239472157970562#photos/107279198486276596870/albums/5999239473407968129/5999239472157970562?pid=5999239472157970562&oid=107279198486276596870