I get chest pains and insomnia when my synthroid is too high.
Do you mean thyroid medication (thyroxin) or anti-thyroid meds?
Too much thyroxin or T3/T4 is a high FT3 with shakes, severe anxiety, diareah (sp), hot sweats, very fast heartrate.
Too much anti-thyroid meds is coldness, slow heartrate, lethargy (no energy), constipation.
Although symptoms can be both but I usually go by my pulse, my bowels and my mental state.
Hope that helps.