Achy all over, especially lower back, slight nausea, congested.... etc?

HI, I just turned 16, and I have the same thing. My throat is thick, and puffy, making it hard to swallow, and it feels dry and raw. I'm achy too, also in my lower back and sides. My best guess is it is the newer strand for the flu virus, that hurts your body as well as your throat and nose. The temperature fluctuations are most likely due to this, and how at times the blood seems to rush to your legs and they feel hot, but at other times it is focused on trying to clear your throat and lungs of the infection, and your temperature goes down. I took mine an hour ago and it was about 100, but i took it again and it was 99, then 98, then 99.6, so going up and down may be caused by this. If your fever keeps going up and down harshly, or your legs and back continue to hurt, take some medicine and ask your parents to take you to a clinic or to see what they think you have. Best of luck to the both of us. :]