Not always, by adding the honorific "お" it makes certain words politer, this is not just for questions. Also お is usually for words of Japanese origin, theres also the honorific add on "ご" which is usually for words of Chinese origin. When/which to tag them on is based on the individual words, you just have to know if it takes it. However there are some words which almost always have an honorific to it for example; おなか = stomache, おかし = sweets, ごはん = rice etc...