Try using a different size tampon and make sure you're putting it in right you shouldn't be able to feel it
Another thing it could be is a yeast infection. It sounds gross but it's painful it happens to me every now and again. When it does I can't use a tampon comfortably
Now, were you able to use tampons before? Or were you never able to use them?
I wasn't able to use tampon until I was much older. Some girls just can't.
It could be you are using one that is too big for you. Maybe stick to pads for a little bit then try again later.
What I did when I first started using tampons I would squat down & use a mirror but if your in a public bathroom u can always bring a compact mirror & squat on the toilet seat I hoped this helped you
Ps the mirror is so u can make sure you are putting it in the right hole ( sorry for the TMI )