i wonder what your neuro exam showed.
personally i don't like your dr's attitude. he doesn't seem willing to look further than his nose to find out WHAT the problem is.

your sx's (symptoms) don't sound like fibro to me.
what does your pcp say?
IF you have an mri insist on it being with & without contrast. contrast may show any lesions better that without. and the mri is usually brain & the c-spine area of the spinal cord.

please don't think you definitely have MS because you might not. however, i agree with advocating for yourself so your dr doesn't dismiss you.

you might even try a new dr until you find someone who will listen and work to get to the bottom of things. in the meantime start to collect copies of your test results and dr visits. if you see other drs they will want to see your records.

please let us know you make out. and, try keeping a sx journal with dates and the sx's you have. it's a good physical hx for drs.