It doesn't necessarily mean that you don't have a chance to be hired in, especially if the assistant manager has a lot of autonomy in selections as far as job candidates. The delay might be caused by them interviewing other candidates, the need to review the candidates with the store manager (as a courtesy), or (hopefully not) they did make a decision and forgot to notify all of the applicants. If someone from HR has not let you know either way after about 7 days after the interview, call or follow up via email. I work in HR myself, and my take on it is this: if I'm doing my job correctly, I won't be bothered by you calling since it's reminding me to do my job--COMMUNICATE with you and let you know what is going on with the position and your application.
Good luck with the job, and I hope that you get it!