Painful sex

i recently lost my virginity to my boyfriend but when ever we do doggy the pain is horrible i don’t know if this is because i only recently started having sex but it’s the only one that puts me in this level of pain. it feels like his dick is going into my stomach but not in the way you want it to like i will feel pleasure but the pain will just ruin it for me and i have to hold something to try and let the pain out if you get me. it is his favourite position so he gets carried away and gives goood strokes but the pain just comes midway and ruins it. it doesn’t happen in any other position like missionary for example i feel no pain at all and it’s just pleasure and orgasms but i can’t reach that level with doggy. i don’t know if it’s something to do with my body just not able to handle the position or if my vagima is too tight for it but if anyone has any help please help cause the pain is awful and i don’t want to have to fight through the pain to get the pleasure that i know is there