Rgb/Black line that shifts to several line then to black. How to fix?

So I have a 6-7-year-ish old Sanyo that has had a black solid line down the left of thw screen that measure usually .7 inches. Over the years it's been shifting to become thinker and sometimes smaller. Now, however 1/4th of my screen will stay black from where the line was located, it takes it about 30 minutes and then changes to the solid black line surrounded on both sides with very tiny 1mm color changing lines, then after another 30 minutes it will shift to the regular .7 inch black line. It does this everytime I turn on my TV and only started doing it in the past month, what can I do to fix it, it seems like there is a loose connection but I don't want to do anything major until I know what the problem could be for sure. Thank you.