welcome to NT sally,

i don't know why your dr doesn't want an mri of the area of your back that's hurting. just imho. maybe it doesn't relate to numb areas but it might be something else. as long as you're in the machine. i don't know about cost.

IF they're looking to rule out MS having with and without contrast might be better. IF you have any active lesions they're more visible with contrast. it's worth asking about.

while you're there ask for a copy of the cd and get a copy of the report. you might have to go back to get it. start a medical file on yourself in case you see any other drs.

please let us know how you are.