Tampons and pads

Rowan • I`m just here to track my period
I am 17 and have always used pads until recently when I wanted to go swimming and used a tampon. I had a semi easy time getting it in, but it started to like hurt me and give me cramps after a while. When I tried to take it out, it hurt like HELL and now I'm too afraid to use them again. Why did it hurt me like that?