I Just Had Sudden Painful Cramping In My Upper Abdomen

I just had sudden painful cramping in my upper abdomen and I started to sweat. I was sitting up cross-legged. I laid down, straightened my legs, removed my upper clothing, and proceeded myself to belch. Both symptoms stopped within about 90 seconds. It was painful enough that I thought I might have to call 911. It's been about 15 minutes with no recurrence. I am a 77 year old female with severe COPD, severe osteoarthritis, and moderately severe osteoporosis and I am currently constipated. What caused this, gas or something else?