I have been experiencing the same problems, I'm 25, I feel like i cant sit down with these pains although i feel i need to go the toilet sometimes & everytime i sat down it felt 10 times worse. I went to my doc and was told it may just be UTI, but was still getting the pains after an anti b was given to me. I was then given a referrel to my nearest hospital, who thought it my be my appendix, again this was wrong then thought then it maybe a cyst. The pains then stopped i was sent home not knowing what was going on and had an appt for 2 weeks later to have an ultrasound. I got a scan done to show i have a retroverted womb, they now ruled out it may be a cyst but said i could have a little cyst in the womb and not sure if this is causing the pain, I think this is the problem, I am now waiting to go back for another appt to see a gynecologist which is not till early next year, But hope this may help you out.
I just went to the doctor for the same symptoms and I was told it was diverticulitis. It might be something to look into. Hope this helps.