giving him a BJ

I enjoy sucking my S/O dick , Its just a great feeling knowing he enjoys it ALOT I guess , anyways when I do give him head his dick reaches where that thing hangs from the top of my mouth and i gag , it sucks alot but i wanna go further. it doesnt reach just there , it just stops there cause i cant go further Ive deep throated a couple times but its rare. I also have a jaw issue because the dentist fucked me upwith some stand to open my mouth wider and she put it up so high it hurt and now here we are 🙃 ,I could always open my jaw without a problem I just cant open it for a long time and it wouldnt hurt but now it decides to pop up when I suck dick and I have to stop , its pretty annoying