For A Month Now, I Have Experienced Excessive Heat In

For a month now, I have experienced excessive heat in my body core, beginning in the early afternoon through the evening. Sweat leads to clamminess (then coldness) and a skin sensitivity to clothing where my skin burns until I get into the shower to relieve it. As I am post menopausal I am wondering if this is normal. Could it be an overactive Thyroid? What can relieve it?