Re: why does one get muscle aches/ leg pain when they have the flu?

To answer your medical question.  When the body is invaded by a microbe 
(ie a virus in the flu), the body's immune response (WBCs) becomes 
activated.  The WBCs release chemicals to orchestrate the attack.  These 
chemicals are called cytokines and they are critical in the body's immune 
defense.  For example in HIV disease the virus attacks Helper T Cells 
which are the "conductors" in the "orchestra" of the immune response.  
Helper T Cells (AKA CD4 cells) activate and regulate the rest of the 
immune response via cytokines...if the Helper T Cells are killed the 
immune system falls apart.  Now back to the question.  Muscle aches (AKA 
myalgias) in a viral infection such as the flu are due to the effects of 
certain cytokines on the muscle which produce pain.


Information was attained from a Medical Doctor at University of 
Connecticut Health Center