Hello. Thanks for writing to HCM. I read and understand your question very well. I try my best to help you in this. As you are on levothyroxine , there are many side effect of this drug like Chest pain or discomfort, decreased urine output, difficult or labored,breathing problem,difficulty with swallowing,dilated neck veins,extreme fatigue, fast, slow, irregular, pounding, or racing heartbeat or pulse, fever, heat intolerance, increased blood pressure,increased pulse,, irregular breathing,irritability,menstrual changes,nausea, sweating, tremors etc. I f you have a sever side effect than consult a good physician for this. I hope my advice will help you a lot. Thanks and Regards. Dr Vijay