As you know, I can't give you legal advice here, but I can give you information.
First off, you can only sue for discrimination if you're a victim of ILLEGAL discrimination. That is the type of discrimination based on such factors as sex, race, national origin, disability, etc. - in other words, you would have had to be treated differently BECAUSE you're a certain gender, race, etc. Can you give me more information about this?
Second, there are at least two ways to approach this. One is to sit back and wait until the HOA sues you. You can not only respond, but you can also file a counter-claim, and, of course, ask for attorneys fees and damages.
Another option is to sue the HOA, but it's unlikely (from what you told me so far) that you can prevail on harassment or discrimination. You could, however, ask for an injunction (restraining order) against the HOA, asking that they cease and desist in bothering you about the paint. It seems to me (from what you said) that the HOA's paint color choices/information is vague - that's there fault, not yours. It's also in your favor that you didn't receive a reply from the HOA within a reasonable amount of time.
FYI, for your convenience, here is a link to the state laws pertaining to HOA's:
Going back to your question, it's unlikely that the HOA will provide information to you until the matter is filed in court, either by you or the HOA. Once it's in court, you can request anything that's relevant from the HOA, and they must comply or face court sanctions.
Again, I can't give you legal advice here, and I realize I've only heard your side of the story so far, but from what you've told me so far, your "side" is much stronger than the HOA's "side."
I hope that that helps you. Let's be sure to write back and forth some more if you have follow-up questions. You don't have to "accept" until you're completely satisfied with my answer(s)!
All my best,