A couple things I have heard can cause difficulty swallowing are Hashimoto's thyroiditis and nerve damage. Hashimoto's thyroiditis is an auto-immune disease where the antibodies attack the thyroid. Hashi's can cause swelling of the thyroid. It is more common among women than men and people with celiac tend to get it more also. Actually, celiacs tend to get other auto-immune disease in general. Another possible cause is nerve damage due to low B-vitamins. I have difficulty swallowing sometimes myself. I started taking liquid B-12 a few years ago and it may have helped, cause I don't have that problem very often now.