I experienced this twice in my life but it was not an explosion type sound. Just a very loud sound with a sawtooth waveform, fast attack, ~1 second release.
I've had the same sawtooth sound, in addition to a door slamming. It was while I was quitting caffeine, and made it difficult to sleep when I needed it most.
Hmm, interesting. I've had the exact same sensation/"sound". Though not always that sound, I experience something like this moderately frequently when just about to fall asleep, so maybe it's likely that it would at least sometimes line up well with what others experience.
+1 here. It feels like an electrical pulse, shooting from my head to my body, but the sound is the same.