There are many ways in which sociology and common sense differ, starting with the basic fact that sociology is a formal field of academic study, whereas common sense refers to people's innate ability to understand and assess the things they see and hear on a regular basis. Sociology focuses on the study of human interaction and society, while common sense can apply to human interaction but can also apply to everything from managing one's money to making smart decisions about one's health. Common sense is not a formal program of study (one cannot major in common sense at a reputable university) and does not necessarily involve the use of research and statistical analysis in the way that sociology does.
There may be some aspects of sociology that some people find to be self evident, but to assume that the entire academic field of sociology is the same plane as common sense is reductive and dismissive of the decades of research and other academic work that's been done in the field of sociology. Sociology involves a set program of study that trains students to think critically. Additionally, common sense can be subjective, but sociology is an academic field that requires a measure of objectivity in the form of statistical or research-based proof of theories.