What can cause sore muscles and joints and swollen lymph nodes?

?chronic fatigue sx: One possibility is chronic fatigue syndrome which may be due to a virus (true cause unknown). This is associated with extreme fatigue for at least 6 months, joint pain, muscle pain, swollen lymph nodes and other symptoms. See your doctor to have various lab/blood test to rule out other serious diseases.

Virus or ....: A viral infection for a few days, but more than a week needs to be checked out by a doctor.