I usually go to the gym 3 times a week to weight train and do lots of stretching but have not been since thursday as I had really bad flu on friday but feel much better now, the only thing is i had really bad muscle pain in my back yesterday and it got worse today, is this a symptom of the flu or of not training? how long can i expect it to last?
"really bad flu"...? for 2-3 days? it just came and went?
you did not have flu at all if you are fine now.
you most likely had a cold.
though the back pain could indicate a kidney problem and coupled with your feelings of "flu" - i would suggest seeing the doc to rule out a kidney infection