Migraine involves inflammation and neurons that are over-excited. The two are probably linked.
Inflammation and excitotoxicity: role in migraine pathogenesis.
Summary of the abstract.
The pathogenesis of migraine is still unclear, but much evidence suggests a role of inflammation in pain generation.
Calcitonin gene related peptide, nitric oxide and cytokines are all molecules shown to be involved both in animal and human studies. The glutamatergic system is also described as a possible mechanism leading to neuronal hyperexcitability and cortical spreading depression (CSD).