Its sounds a bit like restless legs. I get this, and calf cramps (mine are due to the tendons in my feet being too short, and can cause cramping up through my calf), and they're quite different.

The leg ache is just that, mine feel sore behind my knees, and kind of like I've done a huge workout the day before.

If you have a bath, I find this is a good option - be careful with empson salts as they can lower your BP, which if your not pg is not so bad, but if you are, soething to be aware of.