I use VGA cable with VGA to DVI adapter to connect my pc with monitor.
I thought its something with the cables but i changed both adapter and cable, and it didn't help.
So, my guess was that i had some problems with GPU. I swiched my default display in BIOS to be integrated and connected it correctly and the same problem was there.
The last thing that was on my mind was monitor. Tried my brother's monitor and still the same problem.
When i flip the picture to the portrait mode it still goes to the right side, so if you flip your head also, the shadow will go up instead of right.
So if its not monitor, cables, GPU or dust (quite new pc), what could it be?