ICD-10-CM > G00-G99 > G40-G47 > G44 > G44.8 G44.8 Other specified headache syndromes Non-Billable/Non-Specific Type 2 Excludes headache with orthostatic or positional component, not elsewhere classified (R51.0) Codes G44.81Hypnic headacheG44.82Headache associated with sexual activityG44.83Primary cough headacheG44.84Primary exertional headacheG44.85Primary stabbing headacheG44.86Cervicogenic headacheG44.89Other headache syndrome