Pelvic adhesions start forming almost immediately after surgery as part of the normal healing process to repair raw tissue. Unfortunately in the process some organs/tissues become "stuck" to adjacent tissues and thus cause pain. Adhesions also develop as normal tissue responds to some form of injury. In many cases these adhesions are painless and the patient never knows she has them, while in other cases they cause a sharp, pulling type of pain, or pain with intercourse or bowel movements.
Adhesions are believed to cause pelvic pain by tethering down organs and tissues. It is not unusual for several organs to be adhered to each other, causing traction (pulling) of nerves. Nerve endings may also become entrapped within a developing Adhesion causing severe pain. Also if the bowel becomes obstructed, distensions will cause pain.
Pelvic adhesions can be filmy (kind of like sheets of cling film), or thick. Some contain small blood vessels. If they involve the fallopian tubes, they can cause infertility or lead to tubal (ectopic) pregnancies. If they are above the liver they can cause pain with deep breathing. If near the vagina, there can be pain with intercourse. And, if they involve the intestines, there can be pain with exercising, reaching for objects above one's head, or when stretching.
Adhesions involving the female reproductive organs -- the ovaries, fallopian tubes, etc -- can cause dyspaareunia (painful intercourse) and secondary infertility -- over 40% of all infertility problems are related to adhesions.