According to your symptoms (moving swelling and fever) you might be experiencing a kind of inflammation but I can't speculate about its real nature. Inflammation could be caused by an infection but I can't say which without further laboratory tests. An immune disorder like an allergy or autoimmunity can also cause similar symptoms. Thyroid gland inflammation (thyroididtis) is mainly an autoimmune disorder.
You may want to consult a rheumatologist or infectologist about your condition.