Tampon won’t stay in

So I’ve been trying to use tampons but they just won’t stay in. I always make sure it’s angled correctly, push it in as far as the applicator can go, and then push it up with my fingers more. I literally can not get it any further in but within five minutes it will be sticking half out. My gyno says everything looks fine so I’m very confused. Has anyone else has experienced this or have an idea what could be going on?