Secret variables are per-repo-slug since they are encrypted with a key that is per-repo-slug. You won’t have them in your personal fork. AFAICS you only have them in your personal fork because you created them anew there in Travis project settings.
External PR builds (builds where the PR branch is from another repo) also don’t have access to secret variables because they are presumed to have untrusted code. Only internal PRs (where the PR branch is from the same repo) have access to them. It’s currently impossible to grant some external users acess to secret variables – see Allow foreign PRs to use secret variables (and you may wish to upvote that FR).
So if you want to have your PR build have access to secret variables, you need to create it not from your personal fork but from a topic branch in the organization’s repo.