Missionary

Okay so hey guys. I have a question. Me and my boyfriend have been having sex for about 3 months. I lost my virginity to him. The first time we had sex we only did the missionary position and it hurt like hell (as I expected). Now 3 months in we mainly just do doggy. I want to master missionary so bad and he wants it too but it hurts me so bad. Can you guys give me some tips on how to ease the pain in that position. Also as a reflex I do lock my legs when he tries to enter (which makes it harder for him to enter) I don’t mean to but I get scared of the pain. Do you think it’s me tensing up that’s increasing the pain? If not please drop some tips on how to master missionary position. Thanks guys!❤️