Right Abdomen Bulge Before BM

I'm not sure if this is quite the appropriate forum for my query, but it seemed the most closely related, so bear with me.

32 Yr. Old Female Smoker, 5'8" 250lbs

Back-story: Two years ago, I had a Laproscopic Adrenalectomy (they removed the adrenal gland from my right kidney through several small incisions in my abdomen because it had a gigantic, non-cancerous tumor growing out of it). I still have both my kidneys, and everything seems to be running properly.

Query: about a year ago, I started getting a kiwi-sized lump in my right abdomen before I have a bowel movement. After I have a BM, the bulge pretty much goes away until the next time I need to poo. The bulge is spongy but firm, and it makes squishy sound if you push on it when it's engorged. There is no discoloration in the skin, and the lump is not visible; although, I'm a big girl, and judging from the size of the bulge, you would be able to see the lump on my abdomen if I were thin. My stomach has always been a little touchy, but my BMs are normal. And it does not hurt, it's a little uncomfortable at times, but it does freak me out just a little.

I'm getting it checked out this summer, but does anyone have any insight into what I might be dealing with here?