I need a user input for my pygame program, but I need it on my GUI(pygame.display.set_mode etc.), not just like: var = input("input something").  Does anybody have suggestions how to do this?
There are some answers already here. Anyway, use PGU (Pygame GUI Utilities), it's available on pygame's site. It turns pygame into GUI toolkit. There is an explanation on how to combine it and your game.  Otherwise, program it yourself using key events. It's not hard but time consuming and boring.
Pygame, user input on a GUI?