Have fibromyalgia, but it's been months since last episode. can there be long intervals without symptoms?

Yes: ? why months-long interval since fibromyalgia (FM) symptoms. This is not characteristic of FM & suggests that person's symptoms remitted. Explanation for such change might be that she has corrected certain causal factors through exercise, weight loss, use of medications, nutrition, and other lifestyle changes. If she truly had FM, her improvement illustrates the multifactorial nature of FM.