Ache and pain in my back, due to MS?

I started walking about two weeks ago and ever since then I have had a really bad ache all over my back and a very sore neck it is very painfull. I have multiple sclerosis and have noticed that while walking my right leg gets very weak and I start to limp (the weak leg is due to a very bad attack I had). I have to stop a few times as it gets very sore. Does any one know if walking with a limp or one weak leg can throw your back and neck out?