Was half-way through my answer when Beth's reply came through...
Of course first check that the feet are ok (is she lame?, possible scald/footrot, shelly hoof with something stuck between the loose hoof part and the soft tissue of the hoof), there is no mastitis in her udder-( has she got an udder yet and if yes, is it hot, hard, lumpy?) and I would also check if any of her joints (pasterns, knee) feel hotter than the other leg. Goats do get arthritis, but I would have thought a 5-year old is nowhere near old enough. How are her pasterns (backlegs in particular)?
When is she due? Did she come with a clear CAE test to you or are you testing her first time?
Maybe you could go back and read through Clydesdaleclopper's post from April 14th, 2014 title.: Poorly Goat -any advice? to see if the symptoms are similar.