MS is a difficult disease to diagnose, and as posted above, not given out willy-nilly.
My neuro, who is well-known for his specialty in MS, looked at my newest MRI and said, "If I didn't know your symptom history, looking at this MRI, I wouldn't be sure if you had MS or not." But based on that plus symptoms that he's tracked over the last 20 months, he knows I do have it.
It also depends on the type of MRI machine. Some are more sensitive than others, and lesions will show up more in the more sensitive machines.

Back 5 years ago, the first neuro I saw said, "Migraines," and handed me meds for that. Made me sick as a dog; I found out what a migraine felt like, cause the meds gave me them. It took me 4 years before I got a "probable" MS diagnosis. And that was after years of symptoms...
So be patient. Make sure your doc is an MS specialist, if possible. And keep notes of symptoms/appointments so you have a record for yourself of what's going on.