Hello dear, Thanks for being on healthcaremagic.com. If you would have presented to me as an outpatient,I would have made the following clinical explanation-This cramp like feeling on left side of your headache may be due to anxiety,manifesting as Tension type headache(TTH).In TTH,it should improve with mental relaxation,tight pressing your scalp and while diverting attention towards some interesting task.Alternatively it can be a migraine variant also,in which it is usually accompanied with- nausea,photophobia,phonophobia,visual aura Please see whether it is associated with the factors mentioned above as it is likely to be a primary headache only,because you mentioned that it is not associated with red flags like slurring of speech or facial deviation.I hope it helps.