Stomach spasms and Nexium

Ever since my total colectomy surgery last November, and especially after my takedown surgery, I've had stomach spasms (not sure if that's what you call it). It's like it even hurts when you lay down, but it's not like an every day thing that I get this.

I got it once 3 weeks after my takedown surgery and that one was really bad where I couldn't even walk. My GI had prescribed me Nexium in the past because he thought it may be from acid reflux (but he did a scope and I didn't have it). I had some Nexium left over so I took one pill and within hours, it calmed things down and it felt like nothing ever happened. Since then, I didn't have anything like that for about 3 months but about 2 days ago, I had another stomach pain (it's like directly below my ribs). Again, I just took one pill of Nexium and it calmed things down. It's not like I have any heartburn or any chest pain or anything that comes upward like acid.

The pain doesn't keep occurring but rather comes every so many months. I've never had any stomach problems till I had surgery.

What are these pains? Has anybody experienced it? I can't relate it to anything. It's not like I can say I ate this so therefore this happened....

Thanks :) I spoke with my dr and he told me that since it's not like a frequent or daily thing, to just take buscopan to help relieve the spasms when I have them. Seems to be working. Thanks!