Not my field, but I wonder if this could have been a case of a bezoar of some kind, perhaps Phytobezoar[0], that got loosened by the massage?

After seeing reports[1] a few years back about the use of Coke as a non invasive way to clean these out, I now drink the stuff when my stomach is upset. With n=1 I can report it has a real effect on me.

[0]: https://en.wikipedia.org/wiki/Phytobezoar

[1]: https://pmc.ncbi.nlm.nih.gov/articles/PMC3292399/