The pain of loneliness exists because it signals harm, danger to you. The US is hyper-individualistic because it serves capitalism. They want you to be alone so that you can fill that "pain point" with all manner of pleasure sold to you. I can only urge you to stop being alone by joining a run club, improv class, and saying yes to every invite. Move to a big city if you don't live in one. You must do this.