Hi,
Welcome to healthcare magic!
Autoimmune
thyroiditis is a self limiting disease usually has a
hyperthyroidism followed by
hypothyroidism. But it has nothing to do with your symptoms, you should continue the thyroxine.
Your symptoms might be related to
hiatus hernia, when hernia is causing local congestion it can cause these symptoms.
You should have a physical examination by your physician and get base line investigations done/repeated like Chest X Ray, Electrocardiogram, Complete Blood Counts, Renal Function Test, Liver Function Test, Fasting and Post-Prandial Blood Sugar, Thyroid Profile,
Lipid Profile, Ultrasound Abdomen.
This work up is expected to detect the underlying problem so a definite treatment could be started.
I hope this advise would be helpful for you.
Still if you have any queries or doubts, please write me back,
I would be happy to solve them.
Wish you a great health!