If you click on My Trackers at the top of the page and go to my Weight, you can add additional measurements to track. That would be one place you could keep track of your pain levels, and then you'd have graph reports that would show you a summary of those readings if you needed it.
Hope that helps,
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford
"No matter how slow you go, you are still lapping everybody on the couch."