What Does My Ultrasound Scan Report Indicate?

I had a full tummy tuck in 2007. 3 months later, had an exploration and irrigation because my incision and belly button were not closing up, I had contracted MRSA, I was being aspirated 3 times per week with no decrease in drainage, ultrasound revealed 4 large seromas, and stitches were protruding. After irrigation and exploration surgery, I was told I was allergic to the stitches. After a year on antibiotics , I decided to see another plastic surgeon. He was able to get all of my openings closed. Ten years later and a total of 4 c sections, I get this 2-3 inch in diameter hard ball like thing that comes occasionally and hurts when I lift, bend, or strain my abs too much. Pain lasts for about 20-40 seconds and you can feel the hardness with your hand. Then it fades. Today, i was swatting at a bumble bee and hit myself pretty hard with the broom handle and since then, this ball has formed atleast 5-10 times. Whereas, before my broom mishap, it only occured when abs were strained. Any ideas what this could be? Do I need to see a plastic surgeon or internal medicine dr? Also, would this be deemed medically necessary for repair in order for insurance to pay? I d like to fix whatever is wrong but at the same time, have my horrific looking tummy fixed at the same time. Thanks for your time.