Something with Shift and the game

So, I was playing a normals game of league right? When I was playing, my teammate got a good kill and I wanted to say "Nice!" When I went to type it, I typed in "N " and it did not respond to any other keys. So, I tried to right click in the game and continue, I thought it was a normal issue with the chat. Apparently, the game did not respond to my clicking either and the cursor turned into the windows cursor. I then was afk for 12 minutes trying to figure this out when I smacked my keyboard and fixed it. It was my Left Shift key that was the problem, when I tapped left shift, the game did not respond to anything. Please contact me when you can