There is only a handful of conditions that can cause such distribution of neurological symptoms.
Considering your young age, multiple sclerosis is on top of the list and with your "scattered" symptoms in head, arm and leg a brain MRI is not enough.
In addition, MRI may be initially negative in up to 10% of pateints with early MS particulalrly if done without contrast.
You need a cervical and thoracic spine MRI with contrast.
Lupus, if negative, should prompt other autoimmune
tests because ANA is not always positive but other more specific tests - SSA and SSB, dsANA could be.
Infectious causes such as West Nile virus, CMV, EBV, etc. can also cause these symptoms.
As important as the MRIs is a spinal tap. They should send your cerebrospinal fluid analysis for oligoclonal bands (MS), immunoglobulin index and viral
PCR and routine studies.