Headaches happen when pain-sensitive structures in and around your head are activated. Your brain itself can’t feel pain, but the muscles in your scalp, the blood vessels surrounding your skull, and the nerves running through your face and neck all can. Most headaches fall into a few common patterns, and understanding which one fits yours helps you figure out what’s going on and what to do about it.
Tension Headaches: The Most Common Type
If your head hurts with a dull, pressing sensation on both sides, like a tight band wrapped around your forehead, you’re likely experiencing a tension-type headache. These are by far the most frequent kind. The pain is mild to moderate, doesn’t throb, and usually won’t stop you from going about your day.
The underlying cause involves heightened sensitivity in the muscles and soft tissues around your skull. In people prone to tension headaches, these tissues become significantly more tender than in people who don’t get them, and the tenderness tracks with both how intense and how frequent the headaches are. Inflammatory chemicals released in those tissues excite nearby pain-sensing nerves, creating that familiar ache.
When tension headaches become chronic (15 or more days per month), something more complex happens. The nervous system itself changes. Pain signals from the head and neck get amplified in the spinal cord and brain, so stimuli that wouldn’t normally hurt, like light pressure on your scalp, start registering as painful. People with chronic tension headaches also become more sensitive to heat, pressure, and electrical stimulation all over their body, not just in their head. This widespread sensitivity is a sign that the pain processing system has been dialed up centrally, not just locally in the muscles.
Migraines Are More Common Than You Think
Migraine pain is typically throbbing, often on one side of the head, and moderate to severe. It frequently comes with nausea, sensitivity to light, or sensitivity to sound. Some people experience visual disturbances like flashing lights or blind spots before the pain begins.
The biology of migraines centers on the trigeminal nerve, the major nerve supplying sensation to your face and head. When this nerve becomes activated, it releases powerful signaling molecules along its projections to the membranes and blood vessels covering the brain. One of the most important of these molecules, called CGRP, triggers inflammation and blood vessel changes that produce the intense, pulsating pain. This pathway is now so well understood that newer migraine medications work by blocking CGRP directly.
Here’s something worth knowing: up to 90% of people who believe they have “sinus headaches” actually meet the clinical criteria for migraine. In a study of nearly 3,000 patients who had been diagnosed with sinus headache by themselves or their doctor, almost nine out of ten turned out to have migraine instead. The confusion happens because migraines can cause facial pressure, nasal congestion, and watery eyes. If your “sinus headaches” keep coming back but you never actually have an infection, migraine is the more likely explanation.
Cluster Headaches: Rare but Intense
Cluster headaches are less common but produce some of the most severe pain a person can experience. The pain is sharp and burning, usually centered around or behind one eye. Attacks last between 15 minutes and three hours and tend to strike at the same time each day, often waking people from sleep.
The clockwork regularity of these attacks points to the hypothalamus, the brain’s internal clock. Brain imaging studies have found that the hypothalamus activates during cluster headache attacks but not between bouts. Because this region controls circadian rhythms, responding to light cues and running your body’s internal schedule, it explains why cluster headaches follow seasonal and daily patterns so precisely.
Everyday Triggers That Cause Head Pain
Dehydration
When you lose enough fluid, the concentration of your blood rises, creating an imbalance that pulls water out of brain cells. This causes cells, particularly those responsible for water transport, to shrink. The result is a headache that’s usually dull and diffuse, often worsening when you stand up or move around. The fix is straightforward: drinking water typically resolves the pain within 30 minutes to a few hours, though severe dehydration takes longer.
Caffeine Withdrawal
Caffeine narrows the blood vessels around your brain. When you stop consuming it, whether intentionally or just because you skipped your morning coffee, those vessels expand. The increased blood flow creates pressure on surrounding nerves, triggering a headache. These withdrawal headaches can last up to two weeks as your body adjusts, which is why cutting back gradually works better than stopping cold.
Screen Time
Staring at a screen for hours strains your eyes in ways you don’t consciously notice. Your eyes constantly refocus to read pixelated text, the contrast between letters and background forces them to work harder, and you blink about a third less often than normal, drying out your eye surface. Add in glare from windows or overhead lights reflecting off the screen, and you get a headache that builds behind your eyes over the course of the day. Taking breaks every 20 minutes, adjusting your screen’s brightness to match the room, and positioning your monitor slightly below eye level all help.
Poor Sleep
Waking up with a headache that feels like pressure on both sides of your head and fades within a few hours could be related to how you’re breathing at night. Sleep apnea, where your airway repeatedly closes during sleep, is a well-documented cause of morning headaches. The formal criteria describe these headaches as occurring 15 or more days per month, pressing in quality, and resolving within four hours of waking. If that pattern sounds familiar, especially if you also snore heavily or feel exhausted despite a full night’s sleep, a sleep evaluation is worth pursuing.
Head Pain That Needs Urgent Attention
Most headaches are uncomfortable but harmless. A small number signal something serious. Headache specialists use a set of red flags to distinguish the two, and knowing them matters.
The most concerning sign is sudden onset. A headache that reaches maximum intensity within seconds, sometimes called a thunderclap headache, can indicate a ruptured blood vessel in the brain and needs emergency evaluation immediately. This is not a headache that builds over minutes or hours. It hits like a switch being flipped.
Other warning signs include headache accompanied by fever, night sweats, or unexplained weight loss, which can point to infection or systemic illness. New neurological symptoms alongside your headache, such as weakness in an arm or leg, new numbness, or visual changes that aren’t part of a known migraine pattern, also warrant prompt medical attention. A headache that keeps getting worse over days or weeks, rather than coming and going, is another red flag.
Age matters too. A new headache pattern appearing for the first time after age 50 is more likely to have a secondary cause than the same headache in a 25-year-old. And new headaches during or shortly after pregnancy should be evaluated for vascular or hormonal complications.
Figuring Out Your Pattern
The single most useful thing you can do is pay attention to when your headaches happen and what they feel like. A headache that shows up every afternoon after six hours at your desk points to eye strain or posture. One that arrives on weekend mornings when you sleep past your usual coffee time is likely caffeine withdrawal. Throbbing pain with light sensitivity that knocks you out for hours is probably migraine, even if you’ve always called it a sinus headache.
Keeping a simple log for two to three weeks, noting the time, location of pain, what you ate and drank, how you slept, and what you were doing beforehand, often reveals a pattern that makes the cause obvious. That information also becomes invaluable if you do end up seeing a doctor, since headache diagnosis relies heavily on your description of the pain rather than imaging or blood tests.