Why Does Neck Pain Persist Even After Thyroidectomy ?

Hello. I had a complete thyroidectomy 5 mths ago and I recently got Sinutitis, so my doctor thinks. I have been taking Augmentin 875 2 x dly for 7 days now and I still have throbbing and pressure in my head, ears, and a very stiff and sore neck at the base of my skull , which is painful and radiates up to my head ( I have had this symptom for at least 3 months). I am taking Cytomel 5mcg 2x dly and Levothyroxine 175mcg dly and I also take bioidentical Progesterone. It seems at times when I take the cytomel the neck pain is worse. I feel fatigued and run down, as though I have a virus and sensations that my body will stop functioning. All of my blood work shows up fine. Can you please help me as to what could be wrong? Thank you