16 cant cum

I am 16 and i have never came . I try stimulating my clit , and its great until i start shaking from the slightest touch then it stops feeling good all together . Anything after that hurts . Fingering hurts way to much also . I've had sex one time 2 years ago but i barely felt anything and it hurt really bad to sit for the next day . Im not allowed top New alone with my boyfriend so i can't have him help me and i refuse to tell my mother . She can't keep a secret . Someone please help me . I tried relaxing, fantasies etc . I don't have access to toys either . This is terrible and my boyfriends birthday is on May 15 , we were going to be alone for once that day but if i can't cum there's no point . We've had phone sex slot so that i can pretend i came but when i hang up i cry myself to sleep for lying to him . I get chills of pleasure if i concentrate and think about dirty things but it goes away after a few seconds . Or if i get turned on , it happens . Ibe never heard of anything like this . I fear this could be a medical issue . Somebody please help me ...