hi luke and welcome to NT,
i don't think there's anything wrong with getting a 2nd opinion, especially when you're dealing with something serious like probable MS. your dr must already had dx'd you if he's wanting to start you on MS meds.

did they include any of your spine in the MRI?
is he dx'ing you with 1 brain lesion?
sometimes doing a spinal can be helpful if they find the results they're looking for which is something called O bands. 2 or more can indicate MS.

you can look for an MS specialist for a 2nd opinion. to find 1 call 1-800-FIGHT MS. they will hook you up to your local MS society and they can send you md's for referral. you can also try to find an MS opthamologist to check your eyes.

these options are your choices to make. you are your own best advocate.
start to keep a medical file on yourself. ask for copies of your mri's and test results. other drs you see will want to see them. that gives you more control over your illness, whatever it may be.

you may also want to research the current MS meds. you will learn a lot about the drugs and you can decide which 1 you want to take, if any at all.

the interferon meds can give you flu-like side effects. i was on copaxone for 10 yrs and have done well. that's a daily shot but no side effects (se's).

i know there's a lot to learn. try to take 1 thing and 1 day at a time.
we're here for you. MS isn't a death sentence. no one, not even healthy folks, can see into the future.

please let us know how you are.