Since I updated to El Capitan I can not open or access my photos.
Could you tell us in more detail what the state of your migration to Photos is?
Have you used Photos already on Yosemite and have an existing Photos Library? Or are you upgrading from an earlier system and need to migrate an Aperture Library or iPhoto Library? Sorry, but your queston does not tell us what you had before the upgrade to El Capitan.
Where is the library you are trying to open? In your Pictures folder? On an external drive?
Did not receive dialoguebox to rebuild.
This can happen, if Photos does not find the library to repair or rebuild.
When you used the key combination option-command, did you double-click the library to be repaired or Photos? If you launched Photos, try again while double-clicking the Photos Library.