My experience is a little different (mgmt consulting) but the problem is largely the same. The one piece of advice I have for your last line is to ask the simple questions - "What do you mean by....", "Can you tell me more about...", "Can you walk me through..." are all very powerful.
If you have nothing to go off of but a rough sense of which part of their day is causing them frustration, you can ask "I heard that (process X) is hard or frustrating. Can you walk me through how that works? Where does it start?" followed by very simple questions to keep them talking - they'll get as detailed as they can for someone who appears to be in a position to help.
If you have nothing to go off of but a rough sense of which part of their day is causing them frustration, you can ask "I heard that (process X) is hard or frustrating. Can you walk me through how that works? Where does it start?" followed by very simple questions to keep them talking - they'll get as detailed as they can for someone who appears to be in a position to help.