What Causes Hot Flashes From Shoulders To Back After A Neck Fusion?

I am female 46 yrs old had neck fusion November 5 c-234 have 2 plates and 8 screws no complications 1 month postoperative started getting hot flashes from shoulders up front and back turns beat red. Nothing at night while sleeping no sweats, just hot. Rest of body can b freezing at times with winter temperatures. Neurosurgen saying it s menopause my age. Spoke with my obeyn doesn t believe it s menopausal that it has to do with my neck surgery. Want another opinion