Have you seen your doctor about this symptom? If not, you should pronto. What kind of arthritis do you have?
I have osteoarthritis all down my back and I have spinal stenosis because of it.
I have stenosis, too. And arthritis in my back, but mine is not OA. The fact that this is affecting your ability to breath bothers me. It reminded me of another form of arthritis, Ankylosing spondylitis or AS. I really think you should get to a doctor to have this evaluated asap. This is a red flag symptom and you do not want to put this off.