Would you say you’re under more than average stress lately? As a lifelong stutterer (29yrs) I found when I’m suffering from a lack of sleep or am more anxious than normal, my blocks/stutters/repetitions...etc can behave differently or become more severe. I don’t have those painful/locking blocks that you describe but I definitely notice a difference in severity during periods of anxiety. Mindful meditation over the last few months has helped my anxiety/stress and therefore bled over into making me *slightly* more fluent overall, in my experience. It might be a singular experience but given that mediation is generally free (tons of ways to learn it online), and you don’t need any equipment or large space to practice, I’d say anyone who thinks their stutter could even POSSIBLY be related to increased stressors should give it a go. It will likely also help to relax the muscles in your jaw over time as you become aware of how the muscles feel. Stay strong, homie.