Phone shock

Last night while standing outside with my kids I had my iPhone 12 mini in my pocket of my uniform All of us sudden I felt the zap on upper my leg , my iPhone that was in my pocket shocked me and let me tell you it wasn’t a little shock it literally made me jump and my hairs on my body stand , scared the crap out of my adult children because they didn’t know what happened ,what would’ve caused that should I be worried regarding my phone doing that again