If the monitor you have is of the Lcd type any screen distortion or color patterns can mean the LCD display has been damaged due to excessive pressure applied to it when cleaning the screen for example.
If the display develops any sort of fine hair line crack, the result can be what you are seeing on your monitor screen.
If you have, or know the monitor has not been dropped, hit or excessive pressure applied to the screen it`s self.
Then it can mean that the ribbons used in the monitor internal to the case have moved or become unfixed from the connection points from the main circuit board of the monitor, to the lcd display ribbon contact points.
This will cause all manner of problems such as what you see from a pink tinge other than...