sex on the iud

ma

hey ladies! so, im 16 and have been sexually active for over a year now. me and my boyfriend are both clean too lol. but, i got my first iud on tuesday (june 8) and i had super bad cramps the first two days but ive been fine since ! some minor spotting here snd there but thats it. well, today me and my boyfriend had sex, with no condom and he came in me. my doctor said i could have sex the day after so i wasnt worried. but .. i do have pain now. like 15 minutes after we had sex, it felt stinging and kinda burning. im not sure if that is normal but please comment below and let me know ! thank you !