You don't have to have it all figured out, just tell them what you're interested in. Basically, from how you talk, you're interested in the clinical track and likely pursuing an LCSW to do individual and group work. Through previous work you've found that you're interested in working with individuals with chronic pain or disability. Then drop in some person-in-environment perspective and talk about how you also want to work with families and communities to understand and learn how to best support your clients. You don't have to say the exact position you want, you're going to school to learn what would be the best fit for you.