The swelling near the neck along with fatigue can be due to thyroid problems. It can be hyperthyroidism. The cause might be the inflammation of the thyroid gland due to infection. There are some medicine which can treat this problem.The best treatment option is the removal of thyroid. For more information visit:
http://en.wikipedia.org/wiki/Hyperthyroidism
http://en.wikipedia.org/wiki/Hyperthyroidism