ovarian cysts every month?

So every month since I've stopped taking my birth control pills (due to unwanted side effects) I've been experiencing a sort of annoying, aching pain in my lower left belly. It usually happens right in the middle of my cycle. Also the pain usually brothers me just on one side of my lower belly. I made a doctors appointment to see what's going on, but I'm scared. Google has me thinking I'm going to need surgery 😂😂😭😭