What does it mean when ur having a migraine and the whole left side of your brain hurts?

Migraine: The brain itself does not feel pain. However, the lining of brain as well as the scalp certainly do. A hallmark of a migraine is its unilateral nature. So the fact that you hurt on one side fits with your diagnosis.

Migraine: Some people get migraine only on one side of the head. If this is something new or changing character you should seek medical help to check for any other causes.