Hello NotVeryTechie, a very simple way of doing this is by using this logic.
Create an array of questions (below I used 3 questions), and select a random id from the array using rand(), and then print out the value.
$QuestionArray = new array(3);
$QuestionArray[0] = 'Question 1?';
$QuestionArray[1] = 'Question 2?';
$QuestionArray[2] = 'Question 3?';
$myRandomNumber = rand(0, 2);
echo $QuestionArray[$myRandomNumber];
I hope this helps!