In Judaism it is encouraged to ask questions... but are there questions that may hurt feelings of the jews or questions for which even the asker can be punished? So where is this line or border? What can you ask and when do you need to keep silent, and asking is forbidden? Are there sources that asking is forbidden for some reason? For example, we know Moshe was a man of silence. Thank you.

Shalom! Firstly, we don't do or prohibit actions because of fear of punishment, but rather by whether or not they express our eternal and Godly ideals. Punishments are either just a natural outcome of something negative, or set as a deterrent to prevent such an action. Asking questions and striving for truth, is an ideal, where Avraham and Moshe even asked God questions about His actions! Of course, hurting anyone's feelings is forbidden, but there are always ways to clarify the truth respectfully, by asking in a way that isn't offensive. For example, even if your question contradicts something that a rabbi just said, if you ask it at another time, or to another rabbi, it's not offensive. Sometimes asking anonymously, or in frameworks like this, can also be a solution. Additionally, one must have humility and patience in questioning, for example, knowing that some issues may demand years (!) of introduction before I can understand. Sometimes time, either that of the rabbi or perhaps the framework or maybe sundown (!), doesn't allow for an immediate answer. Silence to listen and not to offend is great, but so is asking, and like always in Judaism and our holistic and unifying understanding, even the seeming opposites don't contradict, and can, should and will eventually harmonize.