Hi dear user I have gone through your question. I can understand your concern. Heartburn can be a sign of Acid reflux, also known as GERD or acid indigestion. This condition is extremely common and occurs when the lower esophageal sphincter (LES) doesn’t close properly,so the result is that stomach contents and digestive juices can come back up into the esophagus. I suggest to meet a gastroenterologist for the right diagnose and treatement of this condition. Feeling shaky is a symptom of hyperthyroidism. My advice is to consult an endocrinologist because you need to do the thyroid tests, to understand your actual thyroid condition after radioactive iodine treatement and to have the right treatement because a major expected side effect of radioactive iodine in patients with hyperthyroidism is the development of life long hypothyroidism requiring daily treatment with thyroid hormone. Don t worry,your symptoms are not dangerous but it is necessary to consult the specialists for the right treatement ad follow-up of your condition. Hope I have answered your question. If you have any doubts then feel free to ask me. Thank you for using HCM. Wish you good health.