What can explain dyspnea with normal oxygen saturation?

Many things : Many causes can give someone dyspnea, ranging from the benign to the deadly, and all with a normal oxygen sat. Best thing is to see your doctor about your complaints.

Few others: Low O2 sat is only one trigger that can cause the feeling of breathlessness. Others including CO2 ,drugs like adenosine,theophylline stimulate peripheral neural receptors in the peripheral Nerves usually via the vagus nerves or directly in centers in the central nervous centers.As is usually the case, it's a matter of how the brain interprets signals,different signals same interpretation