A couple of years ago i was told i had "fluids" in the pouch of douglas but it stated that this could be normal depending on the time of the month. I didn't have painful periods, no endometriosis, but did have one fibroid growing which wasn't a surprise as i have excess estrogen and fibroids love that type of environment. I also found out later that i really did have a thyroid problem after all, after being told for 9 years that i didn't and that my thyroid results were normal. I was also told my iron stores were normal, but they were bottom of the normal range and later i slipped into anemia and i never knew it.
Be VERY careful with lab tests and being told all is "normal". ALWAYS get copies of ALL lab reports so you can take them for a second opinion with a new doctor or on the boards here. With thyroid testing they should do TSH, Free T4, Free T3 and Thyroid Antibodies.
I ended up getting help from a good thyroid doctor in the end and before i found him i also found a good naturopath. Both are helping me with my hormones and the naturopath has me on a great herbal mix which has helped make my monthly cycles normal and they have a herb in there to help balance my estrogen and thereby shrink the firbroid. With all the problems i've had, gyno's have only ever pushed me to go on birth control or look at other very invasive treatments and i'm sure hysterectomy wouldn't have been far off. I'm glad i found this healthboard a few years ago and got a few tips which led me to finding the good doctors i have, even though it was 9 years later!!
It's good you are researching all of this now. It's good to be informed about things as unfortunately not all doctors know much about their own profession. You need to look after yourself as it's the only body you get. Cant trade it in for a new one. Take care