Hello lool,
I think the answer to your question is no. Chronic fatigue syndrome or CFS is a separate medical condition. I suppose it cannot be ruled out that a person suffering from AS mistakenly attributes his or her fatigue to AS while actually suffering from CFS, but my guess is that in most cases the chronic fatigue in AS is caused by the AS itself. That is to say, if the AS were cured, the fatigue would be gone as well.
