Tuesday's run started out great! It was 60 degrees and sunny. A perfect day to run. I started out at a good pace, feeling great. Then, at mile 1.5 or so, I got a side stitch. No big deal, I've had side stitches before, and usually breathe right through them. At mile 2, the side stitch moved to the middle of my stomach - and turned into a "bend ya over, stop your running, can't breathe, make you whine" stomach cramp. I've NEVER had a stomach cramp that painful! So I stopped running and tried to walked it out. I raised my hands above my head, took a deep breath, and tried to relax. It took about 3 minutes to subside, then I shuffled the remaining 0.5 miles. With that said, my knee had NO PAIN!
That night, my stomach felt like I did 100 crunches. Very strange. I have no idea what triggered such a spasm, but I don't want to relive that again!
Any thoughts on a cause?

