Thank you for asking HCM
I am suspecting as hypothyroidism
as a cause of your problems.You should undergo a thyroid function test to rule out that.A physical examination of thyroid gland is also essential. A thyroid hormone substitution will relieve your symptoms if this is the cause.A surgical correction might be necessary if you having a progressively enlarging lump on neck.Hope this may help you.
Let me know if you have any further query.