My Acer Aspire e15 523 screen black when powers up. Screen turns on/off when I move it in certain ways like there's a short so

It could be the cable that connects the display to the motherboard, or it could be the display itself. To know which you would need to open it up and check the cable for bends, pinched area, cracks, damage, etc. Also check if it is loose at either end. If the cable seems fine, then the display will likely need replacing.

NOTE: If under warranty, don't open it up yourself. Contact the manufacturer. Also, if you don't feel comfortable doing the work yourself, and it isn't under warranty, then try a local tech.