This seems pretty similar to my experience. Mine definitely improves and declines in phases, although it's more on a weekly to daily basis for me. I think pretty much every stutterer will have certain problem words. Mine are hard B-s and M-s, things like "biology" or "medical". Pay attention to how your lips and tongue move when you say a problem word fluently - they'll probably be moving in a similar way with most of the problem words, although your struggle with L sounds is pretty obvious. Also a pretty complex motion, tongue against teeth.