There are many treatments available for AI diseases but there are many AI disorders so the first step is getting a diagnosis. Since you are seeing the cardiologist tomorrow I would mention your concern about a possible AI disease like lupus, just to get him/her thinking in that direction. He/she may be willing to do some screening tests and refer you to a rheumatologist. They are sometimes hard to get into so ask cardiology office to contact the rheumatologist office and ask for an expedited appointment so you don’t have to wait for months. The chest discomfort may respond to naproxen, an anti inflammatory, if it’s pleurisy or cartilage inflammation, but clear that with cardiologist since you’re on xarelto. A heating pad may help chest also if it’s inflammation and worth a try. Pleurisy causes chest pain with a deep breath, often sharp. Chest wall pain from inflammation of cartilage (costochondritis) causes tenderness upon pressure over the sternal edges or ribs. Both are common in lupus. This will require patience as AI diseases are not diagnosed quickly, so symptom relief is helpful until a diagnosis is made. I wish you luck and a speedy answer and relief!