blue line appears on my screen

I got my Macbook Pro in April 2011, making it an Early 2011 model.
it's been 2 days since I use my MBP in awkward because one thin blue line appear on my screen. It doesn't look that blue when i use applications that has white background colour,but when it has a darker background colour,the blue line showed. And when i do the screenshot, the blue line doesn't appear in the picture, it does look really fine anyone wanna share any solutions or suggestion to fix this problem? because it makes me so kinky seeing that blue line any best suggestion or is there some issue on my hardware? is there any possibility if I do some quick tips by myself? Or if something definitely wrong with my hardware,how much does it cost,since i haven't registered for apple protection plan yet pls help

I've been searching other forums and google for any similar problems, but I can't find anything.
Any help or advice would be great!
Thanks in advance

Does the line change at all when you flex the screen back and forth on its hinge?

I have try to flex it to any degrees, but the line still there. But when I do the screenshot, the doesn't appear on the picture.

The flex test aims to narrow down the cause to the cable connection that goes from the screen to the logic board. If the line doesn't change at all, chances are the cable is OK and the problem is with the panel itself.

But before you get too worried, I would recommend re-seating the LCD cable connection on the logic board. This is fairly easy to do, even if you're a novice with computer hardware. Check out these instructions for opening the case:

Installing MacBook Pro 15" Unibody Early 2011 Display - iFixit

DO NOT follow the steps beyond opening the bottom panel. Once you have access to the logic board, skip ahead to step 13 where it mentions unplugging the display cable. Unplug the cable and then plug it back it, ensuring that it's tightly seated.

I had to do this with my early 2011 MacBook Pro as the cable was loosely seated from the factory.

Is it save if I do it myself or do i have to give it to the professional? But if it save, I will try it. So it means that I carry to step 1 to 4 then jump to the step 13 to 17,right? Feel a bitty lack of confident to do it actually,but if it's save and wouldn't make the problem worst,I think I should try your advise. Do I get right to carry step 1 to 4 then 13 to 17?

It would be steps 1-2, and then jump right to step 13. Remove the connector and then put it back in place.

Is it safe to do? I guess it depends on your skill level with electronics. If you're nervous about it, I would seek assistance from someone who is more comfortable around electronics.

One more thing - if it's under any kind of warranty, then forget what I said altogether (I didn't think about that - but if you purchased AppleCare, then it might still be under warranty and you can take it to a Genius Bar).

No I haven't bought AppleCare too bad Btw I have 13'' unibody not 15'',does it have the same figure inside?