Can your sister keep you out of your parents house to get your personnal items and can she decide what you are supposed to receive for your share of the inheritance?

Legally, your sister cannot keep you from accessing your personal items in your parents' house. As a co-heir, you are entitled to your share of the inheritance as determined by your parents' will or the intestacy laws of your state. If your sister is acting inappropriately, you may need to seek legal advice to enforce your rights.