Tampons and TMI!!!

I’ve had my period for just over 3 yrs now and I can’t use a tampon. Here’s the TMI: I’ve been fingered before and it didn’t hurt so I’m super confused about why I can do that but not put a tampon in. When I try it’s like I just tense up especially if I try more than once then it’s like my whole vagina seals up 😅 I try and do it when I’m relaxed but as soon as instant fiddling with it especially if I use a tampon it doesn’t go in. I think I’m putting it in he right place and I’m trying all sorts of angles. But I only get the tip in I’m using the tampax compak pearls. Really not sure what to do??? And why I can be fingered but not put a tampon in?