It's completely normal for a child to say "my head hurts." Often it's just because they slept badly, are coming down with a cold, or wore themselves out running around all day. So from a parent's point of view, it's easy to wave off. But childhood brain tumors hide right in the middle of these "ordinary symptoms," which is exactly what makes them so hard to spot. Although they're rare, they make up a meaningful share of the solid cancers that occur in children, and because the symptoms tend to creep in quietly and worsen little by little, they get missed in the early stages more often than you'd think.
The signs people mention most often are headache and vomiting. The thing is, they have a slightly different feel than ordinary headaches. If your child complains of a headache the moment they wake up at dawn or in the morning, or keeps waking up at night because their head hurts, that's worth a second thought. The reason is that pressure inside the head tends to rise when lying down, making the pain worse. Vomiting is similar: it's characteristically sudden, coming on without the usual queasy warning. Rather than nausea that drags on like a stomach bug, some children even say their head feels clearer after they throw up.
For a baby too young to speak, you have to look for different clues. In an infant under a year old, the skull bones haven't fully fused yet, so when pressure inside the head rises, the head circumference can grow abnormally fast. The soft spot on the crown bulging tight, or a baby who is unusually fussy, eating poorly, and listless compared to normal—these are changes that are hard to just let slide. Children this age can't put into words "where and how it hurts," so in the end it comes down to whether someone nearby notices that they seem different from their usual self.
Changes in balance or movement are another thing that's commonly overlooked. If a child who used to walk fine suddenly starts tilting to one side or falling often, or looks clumsy when grabbing a cup or writing, it's worth keeping an eye on. The eyes are the same. If one eye drifts inward, things appear doubled, or your child keeps tilting their head to one side to see, it may not be a simple eye problem. Symptoms vary enormously depending on where the tumor forms, so there really is no single symptom you can point to and say "if you have just this, it's a brain tumor."
That's why a "pattern of change" matters more than any single symptom. An occasional headache happens to everyone, but if headaches grow more frequent and more severe over several weeks, or if two or three signs—morning vomiting, a change in gait, a child who suddenly seems sluggish—pile up together, that's when you shouldn't put it off and should get it checked. When you actually go to the doctor, in most cases it turns out to be nothing serious. Even so, getting it confirmed and putting your mind at ease beats letting vague worry grow while missing the right window.
This article is put together only to help you understand the symptoms, and it can't replace a diagnosis. If your child seems different from their usual self, we'd recommend seeing a pediatrician or pediatric neurologist before turning to an internet search.