What can I do if my mother died and the hospital will not tell me anything and my uncle who had legal guardianship will now speak to me either.

We are sorry that you were estranged from your mother and family, and that her death occurred before you could right things, but this is not really a legal question.

If she had no assets there may not even have been a Will nor would it be necessary to appoint an administrator or personal representative or probate an estate.

If there was a Will, as a child you'd receive notice of the probate proceeding. Trying to get further involved after her death, when you were not involved before her death might just increase the estrangement.

One step would be to go to her funeral, if possible, and mourn and start the process of reconciliation with remaining family members. If that's not possible why not go to a clergy person and discuss the situation; many people are comforted by following the rules of their religion in such circumstances.