How can I get my legs to get used to all the excercise I've been subjecting them to?

Lately, I’ve been walking 2–4 miles a day. not including at home or at work. I also go to ecstatic dance sessions once or twice a week. I’m really enjoying the weight looss I’m experiencing because of it (about 2 pounds a week), but my legs are soooooo sore. I started out by only doing this walk a couple times a week, and working up to almost every day. My legs hurt so much that today (I’ve already done my walk, but it was more challanging today) It is a chore to get up and walk around. All I want to do is take a hot bath or get a leg massage. Unfortunately these aren’t options right now. Is there anything I can add to my daily or weekly routine that will make my legs hurt less by the end of the day?