migraine aura without pain

  I have had migraine headaches since I was in grade school.  I finally figured out that it was chocolate that caused them.  However, I am now in my forties and am experiencing the aura of the migraine but not the pain.  I am not eating anything unusual.  Is it possible that I am allergic to something else that would cause this?  I haven't been able to tie any one particular food to the episodes.  And why would I now be experiencing the aura and not the pain?  
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The problem you describe is a well described syndrome - ACEPHALGIC MIGRAINE
(acephalgic means " without head pain ")and is frequently describesd as a
variant of migraine in adults, less frequently in children.
It is basically an incomplete from of the migraine phenomenon, for some
unknown reason the brain does not go on to produce the characteristic
headache.
Acephalgic migraine can be produced by the same triggers as regular
migraine, but as you learned the hard way in childhood finding those
triggers is a matter of trial and error.
It is entirely possible that these are being produced by some form of
food or enviormnmental sensitivity but since migraines do not always
require a trigger this is by no means necessary.
The only way to find out if this is that case is to keep a diary of foods
you eat etc in the day before an attack and see if a pattern emerges,
remembering that a trigger is not always necessary.