@Jarrett There is not any published and documented way to access your stack trace of previous steps in an automation. The good news though is that you really don't need to if you have at least an INFO level log (although for troubleshooting, I suggest setting all categories to VERBOSE). The log contains each execution link and data link (yellow and blue lines respectively). From here, you can easily locate your error and work backwards to see the steps. Below, I'll illustrate how you can make that easier.

The Robot Inspector tool creates a "CMD" file in your %AppData%\Pegasystems folder named "_LogParser.cmd". This can be helpful in reading logs since it can distill your log file down to only the lines you care about. The mechanics of the cmd file are better explained here; https://support.pega.com/discussion/quick-log-parsing. I generally customize the lines I am interested in by starting with only the execution and data links as well as exceptions.

When examining a log for a particular error message, I first start by searching for that message and locating the point at which it occurs. From there, you can backtrack by scrolling up to locate the preceding steps. Execution links will be logged on a line containing "ExecutionLink From:" while data links will be logged on a line containing "propagating From:". This is easiest with a parsed log using the CMD above. I usually use Notepad++ to open log files and will open the parsed log and the full log at the same time. I'll start my analysis on the parsed one to locate where the issue occurred and then backtrack a little to see if I can determine a cause. If I need more information such as matching information or anything like that, I'll switch to the full log.