Thank you for your query.
There are some possibilities of your problem.
Long standing tiredness after thyroidectomy
may be due to hypothyroidism
dose you are taking probably is not sufficient.
Simply t4 & tsh test will guide you about the dose.
Next the pain you feeling at various part of the body particularly the low back pain
should be concerned.
It may be simple mechanical pain.
But the disease recurrence & bony metastasis should also considered.
Nuclear scanning of the whole body have to be done.
Please contact with your concerned doctor.