Yes, it could be a cyst. In my case it was both a cyst, fibroids on my appendix and endo. Weird, random, sharp pains are very normal for people with endo. The only way to know for sure is to get surgery.
The severe pain on the one side could be where a you have a cyst or a build up of endometriosis. I know that is what happened with me. I had sever, sharp pain on my right side. I had to have a laparoscopy done to remove a cyst from my right ovary and that is when they found the endometriosis. They did not know if it was the cyst or the endometriosis that was causing the pain. Once the cyst was removed it helped with some of the pain but I do still get pain on that right side so now they are assuming that is caused by endometriosis. I would definitely mention the episode with the specialist. The more they know the better! Good luck!!!
also, the other night I was having pain that was so bad that I vomitted three times, is that normal? I'm just really confused about all this...I'm only 18 and I just don't really know what to do about all this...