You can have lesions on MRI and no clinical symptoms.
I had my initial MRI due to Optic Neuritis. Diagnosed MS and started drugs. I then went symptom free (still am) but on MRI 6 months later I had 4 new lesions.
I asked the Neuro how I can have new lesions but no symptoms. He said that "brains are remarkably good at making up for deficiencies. It is either on an axon which doesn't relate to physical mobility or my brain is using different connections to perform the same job". It is like you brain has highways but also back roads. If the highway is closed/congested your brain will take the back roads to get to the same destination.
Pretty remarkable.
To answer your question. Yes I personally would treat it. The unexplained numbness and chest pain sound like MS to me. (I have had numbness prior to clinical diagnosis and a lot of people talk about the MS hug as chest pain).
Anyway. my 2 cents.

My MRI stated significant perivemtricular white matter disease . I've had numbness off and on in my left arm and some mild chest pain on the left as well . I've only seen the neurologist once and still processing this new info. Keep me updated on your next scan. Blessings to you !

This answer was very helpful, because I dont feel I have as many symptoms as maybe I should with the number of spinal lesions I have. Brain MRI will be repeated in a month, so I am anxious to hear what has changed, because I dont feel very much different. I was curious about where lesions lay in brain and what it may affect or not.

Thank you

I too have multiple brain and spinal cord lesions with few symptoms, had one bad episode of vertigo which i now realize was an MS attack, I’m taking tecfidera because lesions obviously formed in me for many years prior to diagnosis and I don’t want more forming