This could also be from a goiter or even a stroke. Goiter is more likely. It would be a good idea to check your thyroid, but don't rely on lab tests due to being very inaccurate. Instead check your thyroid by doing your basal body temperature and checking for symptoms of hypothyroidism. Here is info on doing basal body temperature:
http://curezone.com/forums/fm.asp?i=1446516#i
Sea salt will not address all causes of goiter. Goiters occur from decreased thyroid function, so the thyroid enlarges to compensate. But there are numerous causes of low thyroid function including hypothalamic and pituitary dysfunction, hormone imbalances, low cortisol, poor T4 to T3 conversion, etc. Iodine from sea salt will not address these and some other causes.