What is it ..

3-4 months ago i had severe pain going on in the right side of my pelvis .It hurted so bad ,it was worse when on my period ,But only on the right side . Well i went to the doctor (2-months ago ) i did a scan ,he told me i have some liquid there ,But he does not know What it is ,he Said it Could be anything,and i should Wait for the results 2 to 3 weeks , 2 months passed and No results. When i went to see them ,they told me that There's a problem because No results came .

Ocasionally i have some Bad ovary pain along with cramps and back pain even if i'm not ovulating nor on period ...Is worrying me ,i just think at the worst things possible ..in my family cancer is something "normal"

Please if you know what could it be ..Tell me

I forgot to Say that 1 -2 year ago ,something swollen appeard there.