for loop iterated only once
Your button is configured as an input with a pullup.  Therefore, except when the button is depressed to ground that input, this nested loop

while (digitalRead(button) == HIGH){  
   lcd.setCursor(0,0);
   lcd.print("druecken");
}


will endlessly repeat, preventing execution from advancing.

Given that your question fails to state what you are hoping to accomplish it's not possible to make any corrective recommendations.  If you do want to make use of the button, you should probably first search and read the existing questions here having to do with debouncing.