I guess we do not have a definitive answer to this. This question explores the reasons of existence and all reasons have to be personal and individual. Some may seek cosmic reasons for their being here. For example, I may think that I am here because this universe could not work without me or I may simply admit that I do not know why I am here. Instead, I believe, I should create my personal reason for being here.
What you do here should define why you are here. It is you again who should decide what you are doing. I know it is a bit insulting to our ego to know that the universe could do without us.
I truly don't know. I am atheist, but I think all should be able to follow thier own opinion. Hedonism is nice, but many interpret it as drug use and alcohol consumption, which is what many Hedonistic end up doing, drowning in decadence. You aren't going to find the answer here. Search for it yourself. Work hard. Experience life (except for the parts that can kill you, as that may end your search for meaning). You may have known this already, and have been asking just to see others thinking. If so, I congratulate you. Good luck. And if you know the meaning please clue me in. ;)
Well, it would seem that on this forum, it is to read a continuous, monotonous, endless, unrelenting string of people asking "What is the meaning of life?" or “Why are we here” or something closely related, to the point of ad nauseam, all of whom are not satisfied with the thousands of previously given answers, to the same question, many of which are very well thought-out and quite comprehensive.