I can make a case that since the thyroid is an endocrine gland, meaning ductless, and that according to Moritz it will detoxify through the lymphatic system and then through bile and or kidneys, and that if your liver is plugged up, then it makes perfect sense that stimulating a plugged up liver with olive oil will result in your symptoms.
I would also be skeptical that you can feel pain in your thyroid gland proper.
All vegetable oils are high in polyunsaturated fats, some leaning higher in monounsaturated,but nonetheless are toxic to thyroid hormone reception and production.
With all respect to the post below, truly, and with complete respect for the rationale, it is foolish for anyone with any metabolic disorder to not at least look into iodine. Bile issues are downstream of thyroid issues. There is no guarantee that it will fix things but the upside is too high to not experiment.
The downside is that you will further overload your lymphatic system and have similar or worse symptoms as now. But history rewards the intrepid.