G44 - Other headache syndromes
G44.2 - Tension-type headache
G44.20 - Tension-type headache, unspecified
G44.201 - Tension-type headache, unspecified, intractable
G44.209 - Tension-type headache, unspecified, not intractable
G44.21 - Episodic tension-type headache
G44.211 - Episodic tension-type headache, intractable
G44.219 - Episodic tension-type headache, not intractable
G44.22 - Chronic tension-type headache
G44.221 - Chronic tension-type headache, intractable
G44.229 - Chronic tension-type headache, not intractable