Damn, you could have answered my question, or at least, you could have explain Schopenhauer to me. Looks like you don't wanna teach anyone anything, only waiting to be taught yourself. Such an attitude I would call selfish.
Anyway - keep in mind that I hardly know anything about Schopenhauer, right ? All I can do is show why these sentences cannot apply to Epicurus :
> life is nothing but suffering and avoiding pain IIRC till you die
> life is nothing but pain/avoiding pain
First, it's true that the absence of pain is pleasure or provides pleasure. Catastematic pleasure. And it's also true that it's natural to search pleasure. And that pleasure is the only "good" thing.
As a consequence, you could say that life is always about avoiding pain (or endure it when you don't avoid it).
However, such an understanding is based on a play with words. If Schopenhauer is pessimistic (which I don't know), then it would be one point where he differs from Epicurus. Let's not play with words : Epicurus states clearly that the things that keep pain away and that provide pleasure, are precisely the things that are easier to get. As a consequence, pleasure and happiness, which are naturally sought after, are naturally easy to reach. It's the exact opposite of pessimism.
Now, from a very down-to-earth point of view, you could still say : look, Epicurus himself, as a wise man who does not suffer from the absence of any necessary good, the epicurean wise man himself, is still someone whose life consists in pain and avoiding pain ! since avoiding pain is pleasure... If he's always happy, then he's just always avoiding pain !
The thing is, pleasure is not ONLY the absence of pain. The absence of pain is catastematic pleasure. However pleasure can also be dynamic. There's a debate among scholars, as to whether "dynamic pleasure" only applies to the process of satisfying a need, therefore suppressing pain (which is what Epicurus explicitely states), or if "dynamic pleasure" can also apply to non-necessary pleasures (as in : I don't need sex, I feel no pain due to lack of sex, but I'll still fuck this girl). I'm certainly not able to decide, but the key point is that pleasure is not only the absence of pain, even if the absence of pain is pleasure.
(by the way, in case someone less ignorant than you happens to read this : would you guys say that there's a difference between "happiness" and "bliss" ? or whatever the english words are - eudaimon, eudaimonia, and makarios, makaron)