I don't think it is good to do exercising right after fever or when using painkillers, better rest when rest is needed, but then again I'm not a doctor.Had a rest day (again ) yesterday due to a fever all day. I want to get back on track today but I'm not sure if I should. Muscle spams have sent me running for valium (as a muscle relaxant) and tramadol (for the pain).
Yoga on that combination could get interesting...
Do you know about these?
http://en.wikipedia.org/wiki/Exercise_ball
Some exercises might be easier to do using such ball, so that even on bad day there could be chance to do something. Often at beginning it is more important to get enjoyment from doing rather than working out hard.