Nothing to worry!
In Hashimoto's thyroiditis
(Anti TPO high) there can be neck pain
or fullness during the initial period. This will usually subside in few weeks to months time. No treatment is needed - unless pain is severe for which analgesics or short course steroids are tried.
You can wait foe 6-8 weeks and do a repeat thyroid function test and consult an Endocrinologist
to adjust your thyroxine
Hope I have answered your question. If you have any further questions I will be happy to help.
Dr Ajish TP