How is the NATing done between the interfaces? If you are actually NATing those traffic, you won't be able to perform "ping inside x.x.x.x" to ping an external host as ASA does not NAT when traffic is being sourced from its internal interface.
Maybe more information on the actual ASA interface, the NATing that you have configured, also the source and destination ip address. That will help to provide more context into the actual topology.