High occular pressure does not hurt, that is why Glaucoma is such an incidious disease. It pushes back the optic nerve over time and causes a gradual reduction in peripheral field, then blindness. A few points over the "norm" is about where I score and have gotten the lecture many times over the last 35 years. About anything can affect that reading. I have found that pretty nurses bounce the reading up a good 3-5 points

and that the "puff" test is usually high, so most take a second "direct" reading (something like a dial indicator).
Cannibus use reduces occular pressure, probably for the same reason is reduces just about everything else
Headaches surrounding optic problems generally occure not because of internal pain issues, but because there are muscles which change focus and move the eye around.
When these muscles get strained, they act like any other muscles that are over worked. If your focal length changes, the muscles which adjust the lens get strained, causing headaches. IIRC There are no pain sensors in the eye itself.
Swelling of the optic nerve is nothing to fudge with, it can leave you blind as a deaf bat.