"Difficult problems" tend to be the ones that you need a few stiff drinks to forget whenever they come up. There should be no difficulty remembering them.

That being said, what I'd do if I were in your shoes is create 2 copies of your resume: a copy for handing out and another copy annotated with notes for each job you list about what you'd want to highlight during an interview. Every time your current employer has a performance review, update both since that's when you'll be focused on your important accomplishments over the past review period.