ial ▁ve ins ▁are ▁responsible ▁for ▁pain ▁production . ▁ ▁Head aches ▁often ▁result ▁from ▁tra ction ▁to ▁or ▁ir rit ation ▁of ▁the ▁men ing es ▁and ▁blood ▁vessels . ▁ ▁The ▁pain ▁re cept ors ▁may ▁be ▁stim ulated ▁by ▁head ▁tra uma ▁or ▁tum ors ▁and ▁cause ▁head aches . ▁Blood ▁vessel ▁sp as ms , ▁dil ated ▁blood ▁vessels , ▁infl amm ation ▁or ▁in fection ▁of ▁men ing es ▁and ▁mus cular ▁t ension ▁can ▁also ▁stim ulate ▁pain ▁re cept ors . ▁Once ▁stim ulated , ▁a ▁n oc ice pt or ▁sends ▁a ▁message ▁up ▁the ▁length ▁of ▁the ▁n erve ▁fi ber ▁to ▁the ▁n erve ▁cells ▁in ▁the ▁brain , ▁signal ing ▁that ▁a ▁part ▁of ▁the ▁body ▁hur ts . ▁ ▁Primary ▁head aches ▁are ▁more ▁difficult ▁to ▁understand ▁than ▁secondary ▁head aches . ▁The ▁exact ▁mechan isms ▁which ▁cause ▁mig ra ines , ▁t ension ▁head aches ▁and ▁cluster ▁head aches ▁are ▁not ▁known . ▁There ▁have ▁been ▁different ▁hypoth eses ▁over ▁time ▁that ▁attempt ▁to ▁explain ▁what ▁happens ▁in ▁the ▁brain ▁to ▁cause ▁these ▁head aches . ▁ ▁Mig ra ines ▁are ▁currently ▁thought ▁to ▁be ▁caused ▁by ▁d ys function ▁of ▁the ▁n erves ▁in ▁the ▁brain . ▁Pre viously , ▁mig ra ines ▁were ▁thought ▁to ▁be ▁caused ▁by ▁a ▁primary ▁problem ▁with ▁the ▁blood ▁vessels ▁in ▁the ▁brain . ▁This ▁v asc ular ▁theory , ▁which ▁was ▁developed ▁in ▁the ▁ 2 0 th ▁century ▁by ▁Wol ff