What are my rights as a non power of attorney after the death of my Mother?

I have one sibling, a sister, who has power of attorney. Our Mother died 4 months ago and there is a will stating everything divided equally between the two of us. I have been the primary caregiver for most of the last 5 years. I have a home in Denver but have been living here at Mother's home most of the time and have accumulated a lot of stuff and want to be able to go through mom's things. Can my sister force me to leave, can she keep things from me, like taking me off the bank account as a convenient signer. She told me but after the fact. I have not taken advantage of any moneys; I only pay her bills.