Hi there and welcome to the forums! This is a great place to meet people, find emotional support and learn!
You are not alone when you stated you have gone to a Neurologist and they surmise that your symptoms are of a somatization because there lacks proof of why you're having it.
However, here's a link in regard to MS and negative MRIs written by our forum leaders Quix:
http://www.medhelp.org/health_pages/Multiple-Sclerosis/How-Can-a-Person-with-MS-Have-a-Negative-MRI/show/161?cid=36
You can also browse through the health pages too to learn a bit more about the disease. A lot of people here can give valuable and useful information due to experiences and those who are definitively diagnosed with MS as well.
I'm sorry you're going through all of this. As I said, you're not alone.
I agree with what Paula says in that MS is a difficult diagnosis to obtain. The doctors (PCP and Neurologist) figure out if you are having mimics of the disease. There is a long list too.
Your journey will be long and frustrating at times, but don't give up. You have us here to listen, support and guide you along the way.
Lisa