Thanks for the query,
Ovarian cysts can and do occur after a hysterectomy
You may develop a functional cyst or a complex ovarian cyst after a hysterectomy.
Less likely PCOS
Although most ovarian cysts are benign, though complex cyst could be malignant as well.
Get an Ultrasound
and Ca 125 levels.
If your ovarian cyst is benign and only small in size, your doctor may recommend that you wait for two months before series of investigations.
If your cyst has continued to grow over the period of several months, your doctor will likely recommend that it is removed.
Hope this helps,