Features are suggestive of Multinodular Goitre. I suggest you get a Tc99 Nuclear Thyroid scanning done to evaluate the thyroid functioning and to rule out malignancy. This is done routinely at most Cancer Hospitals. Since you are close to Chennai, you may visit any of the Cancer Hospital there equipped with a Nuclear Medicine department. Here in Bangalore, I routinely send my patients to Dr Kallur at HCG Hospitals on K R Road, who is the most experienced in this field.