Hello and welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
The most common cause of pain in the thyroid gland is
subacute thyroiditis.
In these cases you may have thyroid tenderness but at the same time you may have fever and symptoms of
hyperthyroidism followed by symptoms of hypothyroidism.
Your doctor will be more likely to check for subacute thyroiditis if you’ve recently had a viral infection in the upper
respiratory tract.(and this is not your case)
From your description i deduct that probably your problem is not due to the thyroid gland.(because your symptoms disappear after you drink fluids, you have not symptoms of hyper/hypothyroidism and your had not an upper respiratory tract infection recently.)
Anyway,You have a
multinodular goitre.
For this reason i suggest to do the thyroid tests TSH,fT3 and fT4 to see if you actually need a medication for your thyroid condition.
Second suggestion is to consult a local
ENT specialist to check for the right cause of your actual symptoms.
Hope this information is helpful.
Let me know if i can assit you further.