LCD screen looks like bad TV reception

My laptop LCD screen starts up and looks fine for about 10-15 minutes then begins to do what looks like bad reception on an old TV and sometimes freezes the image on the screen. If I gently squeeze the left side of the bezel the picture comes back sharp and clear. If I power down the laptop for 15-20 minutes it starts up and works fine for another 10-15 minutes. When the problem starts, I have tried a clothespin to maintain pressure on the left side bezel and that works for a few minutes but then goes bad again. I can move the clothespin up and down the bezel to "chase" the problem and that works but I have to move the clamp every couple minutes. I have looked inside and actually pulled the LCD out of the bezel to wiggled the video connection and inverter connections but they don't cause/cure any LCD problems. The only thing that seems to work is applying pressure to the left side of the bezel or LCD frame directly, pressure on the top, bottom or right side does nothing. Also, when the computer starts up and is working fine, moving the laptop or changing the screen position has no affect on the image but once the problem starts, movement will increase or sometimes correct the problem. When I connect an external monitor I have no issues at all on the external screen even when the laptop screen is "wigging out" or freezes. Any help or suggestions are greatly appreciated. Thanks