Even small fibroids can cause pain depending on where they are located and the form they take. Ovarian cysts can also cause pain. In addition, endometriosis is very common and often accompanies fibroids since they are both characteristic of estrogen dominance. The only way to diagnose endo is to do a laproscopy because it will not show up on any scan and there are no tests for it so it is good that you are having one done. Endo alone can range from no pain to incapacitating pain. I had 3 fibroids and also endometriosis and the fibroids were removed during a myomectomy and the endo was lazered. I was in a lot of pain just before and through my periods, but I could some pain when I would use the clutch on my car. I have been so much better since I had my surgery! Many doctors are not familiar or do not know how to perform a myomectomy and will offer a hysterectomy as the only option in more extreme cases. Unless your situation is severe DO NOT have a hysterectomy! If you have endo a hysterectomy may not take care of your pain and there are a lot of unexpected effects of a hysterectomy that many women do not realize.
In the meantime you may want to do some research on natural progesterone cream (I like Emerita) which helps balance estrogen, and also on DIM which is a supplement to help with estrogen dominance. Cleansing, diet, excercise and stress management are also important.