If I am correct, you asked if we as humans can always find a new question for which we do not know the answer, meaning that there will never be a human that knows the answer to any question he can ask.
I think that the answer is yes. For example, you can always ask, what is the next prime number?
If your question is about the number of question that it is possible to ask in this universe, given that there is a finite number of particles with a finite number of states and a finite number of possible transitions, you cannot have an infinite number of questions in a finite interval of time. This means that humans cannot ask or have asked at any given time an infinite number of questions.