I know when I'm pregnant when my sciatic nerve starts acting up (around 4 weeks). Someone once told me that it "shouldn't" until you're pretty big. I told her to tell that to my backside, because it must not have gotten the memo.
Everyone is different, so I wouldn't worry about it. Talk to your doctor about things you can do to relieve or at least lessen the pain. GL!
Yes it is normal. It can sometimes mean that you are deficient in Vitamin C or B or Potassium (or sometimes deficient in all or a combination of those). Iron deficiency can also contribute. Even if you're not deficient in those things leg cramps can occur as a normal part of pregnancy due to hormonal symptoms. My legs were the same way at 4 months all the way to the end.
I googled Pregnancy RLS for you and this is what I found to help you aleviate the symptoms: