I have a benign ovarian cyst (2cms)- could this be a cause of cramping/discomfort after ovulation/luteal phase? i have had this cyst for 6months

Unlikely: 2cm cyst is not the likely cause

"2 cm cyst": Although a "2 cm cyst" will not generally cause symptoms as described, the "cramping/discomfort after ovulation/luteal phase" may have been caused by a much larger cyst which ruptured before any additional pelvic ultrasound was performed. It would be interesting to see if any fluid was found in the cul-de-sac, which could substantiate the prior cyst if ruptured.