I made a thread about the upper right hand, and I think it's normal. That's where the sim tray and locking pin are (locks the display into the body). This means there's some space there to allow the screen to move a tiny bit, and possibly make a click/creaking noise when pressure is applied in the upper right hand side. Another thing to note is, I noticed that the rattle from vibrations also seems to come from this part of the phone, though, applying pressure in this area did nothing to make the rattle less for me, so it might be internal like the pin.
Regarding the click in other areas of the screen, it's quite possible that the screen did not seat well when it was assembled. You could theoretically fix it yourself, but you might possibly void your warranty, as it requires you to remove the lock pin, remove the screen, and reseat everything again; pretty easy process, but possibly could void your warranty. Perhaps if you apply enough pressure it may cause the display assembly to lock in, but I'd advise against it. The easiest thing is to probably just swap it out.