When i push weights at the gym (squat s) i develop migraines headaches. what?

Are you breathing?: When we exert ourselves as such, we tend to hold our breath, stabilizes the core and helps us with the heavy lift. But that pressure build-up can give us a headache. It's important to breathe out while you're on the positive phase of the lift and breathe in on the negative part. Could just be from squeezing your scalp muscles too, as you wince during the heavy lift.