Whats wrong with me?

i had my son when i was 17 he is now 9 since then i keep getting really bad pains in my stomach right at the very bottem i got sent to hospital stayed there for a week on a drip but they never new what was wrong with me iv been checked for stis and every think is ok doctors put me on antibiotics all the time and the pain keeps comming back its so painfull like a burning feeling i cant even stand up straight iv been trying for a baby since a yearand a half ago but no luck im starting to think iv gotendometriosis but to get checked for that they have to go threw your stomach im scared but im sick of not knowing what the painis.. doctors have left it so long it could have made me infertile.. also iv had a scan and im ovulating.. i get very bad period pains as well. ans pain when i have .. please help.