What can I do about my tense neck?

What can be the cause of a lump on the left side of the neck?

• My boyfriend developed this lump on the left side of his neck. According to him, it started on the second week of December and it started growing. I cannot tell how big it grew into or how big it is now because I can only see through the webcam. He is in the US Navy and is stationed currently in Japan. The corpsman and Doctors in his base did a check up and they told him straight out that they have no idea what it is. They are doing a follow check up tomorrow again. The lump, according to my boyfriend, does not hurt and he does not have any other pain/malfunction in other parts of his body. He can move around his neck and it doesn't seem to bother him, other than the fact that the lump itself is not going away and it seems to be growing. Does any one have any idea what this could be? Or what do you think he should do? Since he is stationed in Japan, I am always afraid he is not going to get the full care and attention he deserves in this matter.

• Answer:

  Probably a goiter, a swelling of the thyroid gland. Could be hyperthyroidisim, could be thyroid cancer, could be just a swollen thyroid. Hopefully he can get to a doctor that knows what he's doing, because thyroid cancer is often overlooked.