I'm developing a media player. Right now it's a simple window with a button to load .wav files. The problem is I would like to implement a pause button now. But, when playing a audio file the GUI isn't accessible again (no buttons can be pushed) till the file is done playing. How can I make the GUI dynamic while an audio file is playing? 
I'm using PyAudio, and their implementation doesn't allow this.
Probably you have to use threads for that. You have to play your audio file in a different thread than the gui mainloop so that the GUI keeps responding user input.
IMHO, wxpython is not so complicated and has some utility functions that would help to do what you want. Check the wxpython demo, you have several examples there.
Python/Tkinter Audio Player