Why ask?

It is of our nature to ponder what we experience. Unless I misunderstand your question, it's like asking why we get angry, or sad, or hungry.

1) Looking for some data.

2) Looking for advice. 

3) Looking to share an opinion and wanting to know what other people are thinking about the same topic.

4) Cause interacting over a mutual interest is fun.

 5) Make friends.

Personally I mostly ask questions in Yedda when I can't find the answer on Google or using other search methods. Or, when I'm looking for an opinion or a reccomandation rather then objective information.

An approach to finding the answer may be to exlplore the ability of humans to ask questions as a biological difference to animals (http://yedda.com/questions/Animal_consciousness_animals_6276213331457).