A 22 on the ACT is below the average score for students accepted into medical school. While it's not impossible to get into medical school with a 22, it significantly reduces your chances. Medical schools look at the entire application, including GPA, MCAT score (which is a much more heavily weighted factor than the ACT), extracurricular activities, letters of recommendation, and personal essay. A strong application in other areas could potentially compensate for a lower ACT score, but it would need to be exceptionally strong.
In short, a 22 ACT score makes the path to medical school much harder, but not completely impossible. Focusing on improving your MCAT score and building a strong overall application is crucial.