Pain during sex?

I have never had this pain before. It is deep in my pelvis and can hurt for a bit after sex. It is a sharp and can have a real throbbing feel afterwards. 
It is making me upset because I enjoy sex with my boyfriend and want to have it yet it is sometimes way too painful. 
I have been checked for STI and have been cleared four times. I have cysts on my ovaries yet my doctor has said that they are normal and supposed to be there. 
I have been referred to a gynaecologist yet haven't heard back from them after a few weeks. So I haven't seen them. 
This pain has been going on for a few months now. I'm worried it may be endometriosis. I am only 20 years old and my only want in life is to have a family with my partner who I have been with for 3+ years. 
Can someone who has endometriosis or similar symptoms please put my worries to sleep or give me advice? 
Thank you in advance xox