TKX, you asked:
"Anyone else have muscle weakness as only symptom?"

Just like Sally said, muscle weakness can be caused by SO many illnesses, you can't really determine anything until you've gone through weeks, months, sometimes even years of watching, waiting and testing.

In the beginning and for about a year my first symptoms were what you might describe as weakness, but I thought of it more as leg tiredness and heaviness. In the beginning my legs would feel like I'd run a marathon even though I'd only walked a block, or when I had gone grocery shopping.

I'd soon have to manually lift one leg, than after a few months, both legs to sit in my car or climb a stair.

Luckily after a few minutes' rest I'd be able to go again without the foot-drop or my legs feeling so heavy. I'd say I would have to sit and rest after at most, 20 minutes of leg use.

But a doctor must order many tests to rule out other possible causes since there's no one test that can confirm MS.

You didn't say if your MRI reflecting lesions was that of the brain, cervical column or thoractic spine, but it can take all three to help diagnose or rule out MS. And unfortunately, lesions can be evident but have no effect on your abilty to function. That's why blood tests, LP's and tests like Evoked Potentials are done, to rule out other diseases.

We wish you luck and we're here for you to talk to and ask questions.