I have got a MacBook Pro with Retina display Mid-2014 model. I cannot open the lid of the device without putting one hand at the bottom and other on the lid, which was not the case few months ago. I purchased this machine last year in the month of October and only a week ago it was the Apple service center for the same issue. Folks there cleaned it and said to me that they can't loose it up any further. My question is, Is this normal?
No, you should be able to open the machine without using two hands by simply lifting the screen, you may find the machine lifts off a little, but it should open without two hands, if not then there is something wrong, but that doesn't meant they aren't wrong, perhaps it is not fixable without replacing a fair chunk of the machine.