If you are having thyroid issues, you might try working on an ENERGETIC level to balance that gland. I have learned through the years, that when the 5th Chakra is blocked, thyroid and throat problems result. We are totally connected to our mind, body, spirit and energy field - we are a WHOLE organism and must look at all aspects of the individual when attempting to bring health issues into balance.
The throat, or 5th Chakra, can become chronically blocked if one has had trauma early in life; is unable, or unwilling to 'say' what has to be said; or is fearful of reprisal when 'speaking our truth.'
Just a suggestion: You might want to look beyond the physical, and go deeper into the emotional causes that may be contributing to your thyroid issues. When I have a client who is particularly constricted or unable to release the voice, I use techniques that aid in opening the throat chakra and releasing the blocked energy that is stuck there.
If you need any more info on this, please feel free to contact me directly through http://www.vivalavoice.com or firstname.lastname@example.org.
I have learned that each individual carries a lot of 'stuff' into adulthood, and that in working with voice, all aspects of the individual must be examined and considered.