Kitty,
I'm sorry - I don't know anything about that particular one. My thyroid tests have all been normal, so I've had no reason to look into it.
On doing a quick google of
levothyroxine, I find that one possible side effect can be
chest pain, and another warning of a drug interaction with
amitriptyline (there may be others as well).
A few weeks back, I did find something (more) on
Human chorionic gonadotropin (HCG) being useful with Intractable Pain in the
Health News forum:
http://www.medpagetoday.com/MeetingCoverage/AAPM/25549
Doc