An ovarian cyst will usually only cause symptoms if it splits (ruptures), is very large, or it blocks the blood supply to the ovaries. In these cases, you may have: pelvic pain – this can range from a dull, heavy sensation to a sudden, severe and sharp pain pain during sex difficulty emptying your bowels a frequent need to urinate heavy periods, irregular periods or lighter periods than normal bloating and a swollen tummy feeling very full after only eating a little difficulty getting pregnant (although fertility is mostly unaffected by ovarian cysts)