Have lupus.chest x-ray showed hyperinflated lungs the past few years but otherwise normal.never smoked. exercise.no sob but do get lightheaded.cause?

See your rheumatolog: There are several sle related possibilities and numerous other causes for your sob. I would normally recommend a high resolution ct of the chest to look for interstitial lung disease and an echocardiogram to look for pulmonary artery hypertension. If you have leg swelling or anticardiolipin antibodies you should also be checked for a blood clot. If these are negative there are next steps.