oh my dear
it's definitely the immune system.
this type of response of body suggestive of an autoimmune disease
underneath. it seems to me what u have is cholenergic hypersensitivity
auto immune state. I sure that u get these reaction of pain and swelling when u r exposed to hot climate, stress both mental or physical. u can get ur Anti TPO and anti thyroglobulin
done to see the extent of thyroid disease
. take selenium
200 mcg as immunomodulator effect. T. cetZine 10 mg at night on a daily basis. I am sure u would just simply feel better. after that u keep me posted.