Hi, I'm a 21year old in a steady relationship. When having sex my partner feels like he is stabbing me quite deep inside, it hurts like a quick throbbing pain. I cannot complete a climax with him anymore since this has been happening. The other day I experienced some intense pain in my vagina to the extent that I couldn't move then it slowly wore down to nothing. I have taken a s.t.i test and nothing came back out of the ordinary. I really want to enjoy sex again. Help