New Ill-Defined Mass

I've had some minor pinching abdominal pain on my left side.  I had been drinking a lot of raspberry lemonade up to a couple of months ago and thought the abdominal pain and worsened reflux was because of that.  I thought I either gave myself something like gastritis or an ulcer, plus had my reflux, which I'm already on drugs for, get worse.  I saw a gastroenterologist because I also had difficulty swallowing fish oil pills.  He decided he'd set me up for an endoscopy with dilation of my esophagus in August, and he wrote off my abdominal pain as pain due to adhesions from surgery since the pain only lasts a few seconds at a time.  Then, he walked out the door.  After he left, I was bothered by the fact that my surgery was 4 years ago for my UPSC (stage IVb) and I'd only had this pain for a couple of months.  He'd gone on to another patient, so I was left wondering.  I had an appt. at my family physician's office later in the week, so I brought it up to him, and I also got tested to make sure I didn't have a UTI, as I'd had some symptoms of that and a history of frequent UTI's.  The urine culture was negative.  My PA suggested I have a CT scan and got one scheduled for the very next day.  Nothing was found on the side where I had the pain, but a mass was found on the opposite side.  A PET/CT was ordered for a few days later, and that showed a very small (1 cm. x 1.4 cm.) mass in my peritoneum.  I had my 6 month follow up with my oncologist's office scheduled for the following week, so my PA told me to leave it up to the oncologist what to do about it.  My CA 125 I had that week was lower than it had been since surgery, 6.3 instead of the 7's I've been having, my abdomen showed no evidence of fluid collection (ascites), and my lymph nodes were normal.  Today, I had an appt. at a different hospital where I'd had my original surgery done, with the gyn/onc who'd done my surgery.  He told me that he didn't know what the mass is.  He said it could be nothing or it could be cancer.  I asked his PA, who'd examined me first, if it could be scar tissue.  She told me it could be a fluid collection from having had my lymph nodes removed.  She said it sometimes happens years after surgery.  Anyway, the gyn/onc told me he didn't want to operate and find out that it's nothing, so he's going to wait 3 mos.,  then order labs including my CA 125 and a CT scan to see if the mass has grown.  If it has, I'll have to have it out at that point.  I'm left hanging, but at least I can enjoy my summer and go on my vacation as planned.  And if the results are that I need the surgery, I'd rather have it in the fall when I don't have as much going on.  Four years is a long time to have been cancer free and (possibly) have it reoccur, but I recently met someone who'd had it reoccur after a much longer time, and she'd also had the same kind I had.  It just means we all have to be hypervigilant after we've had cancer.  My gyn/onc gave me a copy of my scan reports, where I saw that I had scattered diverticula, so now I'm thinking they might be what's causing the pain on the other side.  At times, the pain seems food-related, but I'm not bothered by the foods that normally cause problems with diverticula.  Things like plain crackers seem to bother me, but I can usually eat nuts with no symptoms at all.  I'll write again when I know more in September.