You've got your local git setup (which has your master and sottwell-dev branches), and there is a so-called "remote" set to origin, which is probably something like
[email protected]:sottwell/repository.git.
You can see your remotes with
Your local branches master and sottwell-dev are in sync, but it sounds like you need to push from your local set up to your origin - github.
To specifically tell it to push to your "origin" remote at the "master" branch:
Usually, just telling it to push is sufficient:
If it tells you there are no tracking branches set up, use
git push -t origin master
which will tell it your current branch should by default push to origin/master.