A little history first - One of my initial symptoms was a heavy left leg which lasted approximately 2 weeks. That was back in August of '05. After having a positive LP result and lesions on the brain my neuro came to the conclusion that I have MS and started me on Avonex in March of '06.
Back in Dec of '06, however, I began having a lot of problems with my left leg - lots of pain in my hip if I overdid it such as a lot of walking or climbing stairs. It also hurts if I just sitting with my hip splayed out to one side. After almost a year of this, I went back into to my neuro who suggested I see an orthopedist. I did and she determined it must be trochanteric bursitis. Okay, that's fine. Well, what I can't figure now is if the bursitis is only affecting my hip why does my left knee and my lower leg hurt sometimes? I've had three different episodes where my lower leg has hurt so badly I've had to sit down and stop whatever I'm doing until the pain stops which can last several minutes. I almost feels like someone is twisting and pulling my leg at the same time and I can't move my foot. It's quite unbearable. Could this be something related to the bursitis, maybe a nerve getting pinched or could I be having a completely new episode from the MS? This pain has occurred 3 times in the last 6 months. My knee will also hurt if I overdo it and gives out on me periodically. This doesn't seem like a MS symptom but considering I've only ever had my initial symptoms and never anything new (that I'm aware of), I just don't know what to think.
I have had sciatica for years and my husband broke his hip and now has arthritis in it. For both of us, when these conditions flare up, it not only affects the hips, but the entire leg. Partly because you may be walking differently which puts added stress on the lower leg and causes it to hurt.
Our doctors have told us that when the hip is affected, it can and often does affect the whole leg due to the pain, the way we have to walk, etc.
Right now, my husband is dealing with a smashed thumb. Hit it HARD with a hammer. It is horrible looking and he can't use it. It's also now affecting his index finger because he has had to be careful of the thumb, not use it, carries it differently and that has now affected the index finger because he is not using his thumb normally.
So your bursitis could be affecting the entire leg because of the hip.
TX, as CJRT said, it could be non-MS related but it's impossible for anyone here to say for sure. You should call your doctor -- I think I'd call the orthopedist's office first. Explain what's happening and if they feel you should come in for an appointment there or call your neurologist. Feel better and please let us know what it turns out to be!