Thank you for commenting. I appreciate the info.
Hi and welcome,
It's extremely rare to have MS and not have 'any' brain and or spinal cord lesions, MS literally means many scars....if your rheumatoid factor is elevated a positive test is an indicator of an autoimmune condition but not for MS, off the top of my head RF is associated with rheumatoid arthritis or Sjogren's syndrome, there maybe others though.
I'd be assuming it's an artifact too, a lesion from T3 to T7 would of done a lot of damage, i'd definitely recommend looking into your heart rate, chest pain and irregular heart beat, cardiac issues are known to cause a lot of what you've mentioned, maybe all of it would fit so it would definitely be worth getting this thoroughly investigated...
Hope that helps........JJ