A job search is usually focused on finding another similar position in your current field or industry. It focuses on developing a strategic plan that includes marketing materials – resume, cover letter, LinkedIn profile – reaching out to contacts and using social networks.
A career change is a longer, more introspective process that focuses on taking a look at where you are in your life. A career change can involve changes to your industry, field and/or position. It also takes into account personal issues that affect the changes you want to make in your life.