Hot flashes and nausea are most commonly caused by hormonal imbalances in the body, most notably, by sex hormones. For women, a decrease in estrogen is often to blame, whereas in men, testosterone deficiency can create the problem. Sometimes, the symptoms occur for reasons not related to those hormones at all.
Cold symptoms typically begin with a sore throat that may be mild or severe. After a day or two, the sore throat improves and nasal symptoms, such as congestion or a runny nose, appear. Nasal secretions begin as a thin and watery discharge, then develop into a thicker and darker discharge several days into the illness.
Colds and flu are both viral infections, but have different symptoms. With a cold you will have symptoms such as a runny nose or a sore throat. Flu symptoms come on suddenly and may include fever, body aches or vomiting. While there is no cure for either, there are treatments -- chicken soup, nasal sprays, rest -- which can help your feel better.