I have a Samsung LED screen 23" and today suddenly [about 1/2 hour ago] saw a blue vertical line about 1/3 way in from the right side. It disappears when the screen is white and is most prominent when the screen is black [but not off]. It is present in some intensity at most colours. So it seems this one row of blue pixels cannot dim or change their brightness. I placed my smartphone pretty close to the screen [it was charging for about 8 hours]. Did this have anything to do with it? The screen is just over an year old. What should I do?