numbness in arm

Hello, last week I took the perscribed Migraine Maxalt for the first time for a headache.  I awoke in the middle of the night with heart palpitations, an anxious feeling, and numbness (pins and needles) on the right side of my body (in my arm, hand, leg, and foot).  I also had a cold feeling in my left hand down to my fingertips.  I awoke in the morning with a pain in the left side of my neck which subsided within 5 minutes or so.  The numbness in my left arm did not go away however.  So I went to the ER that evening.  There they did a CT scan of my head and did not find anything abnormal.  The ER doctor chalked it up to bad side effects from the Maxalt which should go away on their own.  He also said that I might have slept on my arm funny causing it to fall asleep.  This was definitely not the case as I am brighter than that.  Plus, had that been the case, I really do not think that the numbness would have lasted for so long.  Nonetheless, I left with comfort in knowing that nothing showed up in the CT scan.  Everything returned to normal within the next day or so as the doctor had predicted.  Now, it is about a week or so later, and the numbness and coldness has returned to my left hand.  I actually had some stinging/burning streaks of pain in my forearm and a rather short visible streak of blueness (about 3 inches long) in my forearm as well.  The color has somewhat resided, but the numbness has not.  I have felt some subtle stinging -like discomformfort in the right side of my neck as well.  I am 27 years old, with no previous condition.  What could possibly be causing this, and should I be alarmed?