Are brain aneurysms painful?
Most people who have an unruptured brain aneurysm don’t even know it’s there. It usually doesn’t cause pain or any symptoms at all.
However, many smaller (not only larger) aneurysms are actually found when investigating causes of chronic headache. Researchers don't know for sure if headaches are directly related to an unruptured aneurysm. One thought is that the swollen blood vessel is pressing into the nerves and membranes/tissues around the brain, causing the headache.
A sudden, severe headache (sometimes called “thunderclap headache”) can be a sign of a ruptured aneurysm. Rarely, you can also have a headache that lasts for days or weeks from an aneurysm that’s leaking a small amount of blood. This type of lingering headache is called a sentinel headache. It’s a warning that the aneurysm is about to burst.