Any (penetration) advice?

Alright so, I’m 22, sexually active with my boyfriend (though due to outside issues like family health problems we can’t be very active currently as I’m living with my parents), and when I’m masturbating I can only do external stimulation. Like, I can’t finger myself, can’t insert my vibrator, hell I can’t use tampons when I’m on my period. Every time I try, I don’t know if it’s because I psych myself out or what, but with literally anything if I’m doing it on my own, I can’t seem to find the right angle or whatever and it feels like I’m just hitting a wall and it hurts.

I’ve had problems like that ever since I first tried tampons, and while my boyfriend has no problems with it, when I do it I just can’t, and it’s frustrating cause I’m tired of only being able to masturbate with my clit.

Any suggestions on how to maybe find the right angle, or anything like that?