Maybe it is more because of thyroid but there always seems conflicting about soy products?
In most pain books that talk about nutrition that state the concern for wheat and gluten. That with many other things though. Also conflicting some will say vegan some will say lean protein/less carbs,some no dairy etc etc. I guess it is about finding what works for the person and obviously if you have an allergy or intolerance not having that item.
For myself I never notice an impact on my pain from foods but some I can't tolerate on my stomach such as beans or spices. That is part of the frustration when making changes if one does not feel benefits but some I would think takes a long time?