Is i messing people up, idk

I don't know if I've messed up a few of my friends, backs/necks and or shoulders

So basicall, I have massaged like around 2-3 of my friends shoulders/neck casually while watching films and what not, they said it felt hell of a lot better after I finished,but a few weeks and or month's later they came back complaining about their neck's and/or shoulders, feeling stiff and/ or hurting