Tampon & Pads Help please?!?

When i try to insert a tampon it doesn't go in far enough so it feels uncomfy and sore, i don't like wearing pads because i feel self cautious incase i leak, do you know any ways of protecting your pants? i use a plastic inserter if that helps. I do a lot of dancing so i don't want to wear pads incase the slide to the side or up or anything. Please help!