thyroiditis or not

I had a blood test recently. Result was: TSH 0.530; FT3 3.08; and FT4 0.934. I consulted an endocrinologist and he wants me to take first, thyroid scan a nuclear medicine laboratory test and return to him with the results after. Another test 24-hour urine test for 2 weeks for Pheochomocytoma.
I experienced some of the symptoms of hyper and hypothyrodism like palpitation, nervousness, irritability, weigh-loss, fatigue, sometimes shortness of breath,sensitivity to cold, muscle cramps and sometimes aches.

My question, are these symptoms really show thyroiditis? Do I really need to take the thyroid scan? It is expensive here and actually cannot afford it. What is the alternative to it? And what is Pheochomocytoma?

Thanks for any advice or information.
feliz