Some with achy legs at night also describe them as being too active. This means they feel like the have to move to alleviate the strange sensations in their legs and even in their feet at times. This can also happen in the arms for some people, though that is not quite as common. These feelings are often caused by overactive nerves. For some though, it is just a matter of too much exercise or even growing pains for the younger ones. Muscles growing and repairing quickly tend to be sore and achy.
If you are sure that your achy legs at night are not the result of growing or exercise, you should consider that you have some overactive nerves in your legs. Some people have this as a chronic problem and there really is no easy answer as to why this is. If you are suffering from this problem and you are losing sleep from it, you should talk to your doctor about this so that you can come up with some solutions. There may be things you can do in your daily life to help and in some cases, you may need some help with medications.
If you have problems with your back, you could very easily have achy legs at night due to the problems with nerves, most notably, the spinal cord. If you have ruptured disc that presses on the spinal cord or on the root nerves, you can sustain nerve damage. Once you have surgery to fix the problem, your nerves may have to regenerate. This means misfires and all types of things going on. You can end up with restless and achy legs, feet, or arms, depending on where the damage was done. Talk to your doctor if you cannot sleep in the weeks that follow your back surgery. You need sleep more than ever at this time because your body needs that time to heal properly.
If you take medications for achy legs at night, keep in mind that some of these can help with pain in other parts of the body. Some medications, like Neurontin, can calm nerves as they heal and regrow, and then can be discontinued. How long you should take such a medication depends on the extent of your damage and how much you are bothered by your nerve regrowth. Talk to your doctor and see if any medical treatment is right for you - never self diagnose. Your achy legs at night may be something else entirely.