Don't be afraid of asking questions. It's a necessity. Lupus has no sympathy. Def call your pcp, and see which way they want to go. I went from "healthy" (little did I know...) to asthma to COPD in less than three years. In the meantime, my heart has been tested multiple times, multiple ways, and it's supposedly fine. In your case, it could be either, or maybe even CNS issues. It's tough to say without going to the doc. Do you have "spells", to where you can do most things one minute, and then the next, you're out of breath, and the undefined pain is there? Definitely don't wait. Write down your symptoms, and call the doc's office.
"There but for the grace of God, go I."
"... His mercy endureth for ever."