Brief Answer:
Thyroid

Detailed Answer:
Sorry to learn about your bothersome symptoms.

Yes indeed it is possible to get subacute thyroiditis more than once over a lifetime.

It is important to diagnose this condition correctly before treatment is begun.

For this, you will need to consult an endocrinologist in-person immediately.

When I see someone like you in my practice, I typically order the following blood tests in addition to a detailed physical examination:

CBC (Complete Blood Count, also known as Hemogram; includes Hemoglobin, WBC and Platelet counts)
ESR
Electrolytes (Sodium and Potassium in particular)
HbA1c (Glycosylated Hemoglobin = your last 3 months' glucose average). Also known by other names such as GlycoHemoglobin or Glycated Hemoglobin or A1c
Liver function tests (SGOT , SGPT, Albumin, Bilirubin, Alkaline Phosphatase)
Kidney function tests (BUN, Creatinine)
TSH (checks your thyroid)
Free T4 (this too checks your thyroid) Serum Thyroglobulin
25 hydroxy Vitamin D levels (ideal range 40 to 60 ng/ml = 100 to 150 nmol/liter)

None of these tests require any fasting and can be done at any time of the day

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Brief Answer:
Follow up

Detailed Answer:
This online forum does not permit prescribing guidance. Moreover, subacute thyroiditis requires a thorough evaluation to confirm the diagnosis and rule out other conditions.
Treatment also entails close monitoring and gauging response to medications over ensuing days and weeks.
You will need to see a doctor right away

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