Final answer:
A chronic headache that is bilateral, non-pulsating, and not aggravated by routine activity is most likely a tension headache. Tension headaches are the most common type of headache, triggered by tightening of facial and neck muscles and associated with factors such as stress and poor posture. Relaxation techniques and mild pain relievers can help relieve these headaches.
Step-by-step explanation:
A chronic headache that is bilateral, non-pulsating, and not aggravated by routine activity is most likely a tension headache. Tension headaches are the most common type of headache, accounting for about 42% of all headaches worldwide, and they are triggered by tightening of facial and neck muscles. They are often associated with factors such as stress, poor posture, sleep deprivation, and eye strain. Although stress may contribute to tension headaches by increasing pain sensitivity, relaxation techniques and mild pain relievers can help relieve these headaches.