Cysts on ovaries can definitely cause pain no matter what the size. Remember, the people doing your ultrasound do not have endo or endo pain so they shouldn't be making statements like that. Endo cysts are called endometrioma.
How did you come to the conclusion that you need your ovaries and womb out (oopherectomy and hysterectomy) in order to stop your pain and suffering? Did a doctor tell you this? Reading between the lines is seems to me that you are not seeing the right specialist or diagnostic team. When you say "mixed in with my bowel" do you mean stuck to it? This is highly likely given the pain you are suffering.
An oopherectomy and or hysterectomy are not necessary to treat endo surgically. Some women do have this treatment and many experience a return of endo so it is not a guarunteed solution. There are specialist endo centres and you need to get referred to one of these. Endo is a comlex disease which is why it has a specialism all of its own and an endo specialist is the most appropriate specialist for you to see. They are not all wonderful but usually better than a misguided gynae...of which there are too many. Many GPs and gynaes are not aware of the existence of endo specialists. Choose one here bsge.org.uk/ec-BSGE-accredi... (on the NHS you have the right to choose) and go to your GP to get them to refer you.
For more information on how to do this see this excellent post by Lindle
healthunlocked.com/endometr... Please look at her other posts on her profile for more info on endo.
Also do a search at the top right of this page for 'bsge' and many more posts on this will appear.
I recently had surgery by an endo specialist to remove endometrioma on each ovary, separate bowel from cervix, removal of all endo adhesions and also fibroids. I'm fine now and still have my ovaries and uterus. This is the type of op you need.