Please help, how much pain would someone be in if they have glaucoma?

Generally none: Glaucoma is predominantly a painless disease with symptoms of visual loss occurring generally later in the disease process. A less common form is acute angle closure glaucoma that is a result of sudden build up of eye pressure, as a result of the drainage of the eye becoming blocked by the iris. The latter is an emergency situation that requires prompt treatment (meds, laser, ?Surg) to save vision.

Pain: There are several types of glaucoma and often people do not even realize they have it until they experience some type of visual loss. It is impossible to determine the presence of glaucoma based on pain. If glaucoma is suspect either by family history or vision loss then the patient should see an eye md immediately!