I have had very mild to moderate pain on my right side of about 10 months off and on, very close to my appendectomy scar, could it be a cyst?

No such entity: If your pain is getting worse, then you need to have a medical examination done either by your PCP(Family Physician) or by your Gynecologist. it is hard to guess the cause of a pain like this unless it is on the scar itself which does remain sensitive for 1 to 2 years after surgery(I assume that you have had a recent appendectomy done...?date)

Ovarian cyst is: possibility, but other possible causes include such things as incisional hernia, entrapped nerve, Crohn's disease, etc.

Most likely adhesion: See gyne for U/S if not cyst the consider an MRI of abdomen.