Your other account would need to earn some reputation to gain those privileges. It's ok to have multiple accounts, but you have to be careful that they don't interact -- they can't vote for each other, give bounties to each other, both vote on the same posts or comments, or anything else that you couldn't do with just one account.
I don't understand why you can't edit or comment on your own post, though. You have to be logged in as that user (I recommend an incognito window for this), but users can always edit and comment on their own posts.
If you didn't register the account and have lost access to it, though, there might not be much that can be done. Sorry about that.