I had a cyst in my Adam's apple area and my doctor drained it with a fine needle and results from the lab came back as normal body fluids. This was done 3 time before I had surgery to remove it. That is when the thyroid cancer was found in my thyroid gland. I had no previous symptoms of thyroid problems. I am not writing this to scare you but your body is attempting to tell you something is wrong. It is highly unlikely that it is thyroid cancer but as Rosa stated in her comment your body may be fighting something and it is important to find out so that it can be taken care of. Stand your ground with your doctor and ask for further investigation.
All the best