Ok unfortunately I'm not having this Shift key problem. So perhaps some hints to go on.
You have two Shift keys. See if the other one works.
Ctrl +t brings up Free Transform. That could be a practical alternative to the Move tool.
Try Windows > Workspace and choose a different workspace. Restart PS.
Third party and Optional plugins can be a problem. Hold down the Shift key when starting Photoshop and they will be disabled.
I'll note that I don't have CS5 installed.
There might be something outside of Photoshop causing this and the code in CS6 and CC might be picking it up.
Examples might be other keyboards installed in your Region and Languages, Hotkeys in your Graphics card controls, and also mouse/trackpad settings.
Some third party utilities might be at fault.
One way would be to create a new user account and see if the problem persists when you use Photoshop there.
This is very unusual and I have done some googling but can't seem find anything similar.
I'll have to leave this open for others to comment on.
Gene