There is some evidence to suggest that gluten sensitivity can affect people with fibromyalgia. Gluten is usually associated with people who have celiac disease. However, gluten sensitivity is something different and many of its symptoms are similar to fibromyalgia, including chronic pain and Irritable Bowel Syndrome (IBS).
A study published in the journal Rheumatology International put 20 people with fibromyalgia on a gluten-free diet. It was reported that over a period of many months a "remarkable clinical improvement" was achieved with a gluten-free diet. It said that non-celiac gluten sensitivity can be an underlying cause of fibromyalgia.
So, try avoiding grains like rye, barley, wheat, and semolina. Many products also contain grain extracts as a thickening agent, so always read the labels carefully. Remember that many alcoholic drinks are also made from grains.