Dull ache pelvic pain on left side

Have had this dull ache pelvic pain on left side since August 2011.  Had an ultrasound at GYN in August 2011 which showed a cyst.  Returned in October still having pain, had another ultrasound which showed cyst was resolved.  Still having pain in January 2011 - ultrasound on the 5th showed nothing but normal follicular cysts on left ovary.

Went to PCP who ordered a CT Pelvis with Contrast.
Results -
Impression:  Small amount of pelvic ascites with left adnexal soft tissue density measuring up to 2.9 cm likely related to cystic left ovary.

What does this mean?