Your diets could be depleting you of iodine levels that you need to maintain your cells better too - hense the joint pain and swelling in the throat area could be a goiter that is fighting to come out.
Are you talking of a calorie controlled diet? If so, this will put the thyroid under stress if you already have a thyroid condition. If you mean a controlled diet of protein etc then it may be that some of the foods you are eating are affecting your thyroid as well.
Broccoli, cabbage, kale are notorious for affecting the thryoid. So too, can many seafoods, which have iodine in them.
You need to talk to a physician about checking your thyroid levels. You may need a full gamut of tests if your back is aching too, as this could indicate adrenal issues.