I've been shot down so many times I get altitude sickness just from standing up for myself.

The line uses a darkly comic metaphor to describe the cumulative toll of repeated rejection, criticism, or emotional “shooting down.” By saying he gets “altitude sickness” merely from standing up for himself, the speaker suggests that self-assertion has become unfamiliar and physically destabilizing—something that should be ordinary now feels dangerous because past attempts were punished. The image captures how chronic discouragement can train a person into self-censorship, making confidence feel like vertigo. In Koyczan’s typical spoken-word register, the punchy exaggeration also functions as defiance: despite being knocked down repeatedly, the speaker is still trying to rise, even if it hurts.