1. A simple Xray of chest can help us rule out other possibilities - since you are telling that you have 10-12 lumps between the ribs on lateral aspect rather than the usual site of costochondritis
where ribs meet the sternum.
2. Since you are already suffering from Auto-immune disorders - Sjogren's syndrome and fibromyalgia
along with ?Ankylosing spondylitis
, the most probable diagnosis of your problem is costochondritis. The next probable diagnosis would be neurofibromatosis or lipomatosis
3. Patients with autoimmune diseases are prone for costochondritis because of inflammation of cartilage
all over the body. It is a self limiting problem and usually responds to your usual medications for Sjogrens / fibromyalgia.
4. Nothing has to be done for neurofibromatosis or lipoma unless they are painful or causing your problem