There are no abnormalities that are revealed on the reading of your MRI that would contribute to your arm and hand symptoms that you describe. It is unlikely that you have a schwannoma but if you had one before, there is higher likelihood that one could be present.
Remember that there are many entrapment neuropathies that can occur in the arm and shoulder (see nerve entrapment on the website). These disorders can also cause arm and hand symptoms. There are also peripheral neuropathies (sickness of the nerves themselves-see website) that can also cause these symptoms.
Dr. Corenman