Deep pain
Deep pain usually occurs with deep penetration and may be more pronounced with certain positions.
Certain illnesses and conditions such as endometriosis, pelvic inflammatory disease, uterine prolapse, retroverted uterus, uterine fibroids, cystitis, irritable bowel syndrome, hemorrhoids and ovarian cysts can be the cause.
Surgeries or medical treatments that involve your pelvic area, including hysterectomy, can sometimes cause painful intercourse. In addition, medical treatments for cancer, such as radiation and chemotherapy, can cause changes that make sex painful.
Emotional factors
Emotions are deeply intertwined with sexual activity and may play a role in any type of sexual pain. Emotional factors include:
Psychological problems such as anxiety, depression, fear of intimacy or relationship problems can contribute to a low level of arousal and a resulting discomfort or pain.
If your pelvic floor muscles are tight due to stress you may have pain during intercourse.
A history of sexual abuse may play a role as well due to the emotional effects
Last, Pain durring one sexual encounter can lead to fear of recurring pain, making it difficult to relax, which can lead to more pain.
In the end, the best way to fix this problem is to relax, go slow with someone you like and trust and use lube and foreplay. If this does not solve the problem, you should see a doctor to make sure its not a more serous condition.