I was wondering if anyone can help me. I'm pretty sure I have an overactive thyroid. My thyroid glands have always been enlarged but never really caused any problems. I've also had a "ball" or something on my thymus gland. Could that be a substernal goiter growing downward? I've had it for years and it doesn't seem to have grown or anything. I had blood drawn on Thursday and they called me this morning saying that my white blood cell count was a bit high. Could that be from my overactive thyroid? Some of the symptoms I've been having are: chronic cough for about a year (when I started taking my high blood pressure medication) feeling like something is stuck in my throat, feeling like I'm not fully taking a breath (mostly at night). I should also mention that I got my HBP medicine changed to one that has no coughing symptoms and it still hasn't gone away.