My Wife Is Experiencing Intense Upper Abdominal Pain (about 4

My wife is experiencing intense upper abdominal pain (about 4 in. above her naval) that is coming in waves every 3-4 minutes. At the end of a wave, the pain shifts around and back toward the kidneys. She is 55 years old. She cannot be pregnant. The pains began after lunch, about 7 hours ago, but have come on strong in the past hour. She just took one Tums tablet--no response yet.