My 10 yo, 40 lb whippet mix, who is in otherwise great shape, has been in a lot of distress the last 4 nights, seemingly having abdominal cramping.She seems fine during the day but in the middle of the night, she gets up very suddenly as if in fear, moves quickly from one spot on the bed to another over and over, jumps down from the bed, quickly jumps back up, whines,her tail is down and she sometimes pants lightly and occasionally shakes.She does not want to lie on her side and assumes odd positions that seem to indicate her stomach hurts. Her abdomen does feel hard but not distended and doesn't seem to be tender to the touch.Her back seems fine and she has no trouble jumping up and down from bed. These episodes last from 1 to 2 hours. Finally we give her a pain killer,tramadol, and that helps her to sleep,and then in the morning she is fine,just a little lethargic.She has no signs of gastric issues-no diarrhea, vomiting, retching, weight loss,appetite loss.We have tried a lot of remedies.We thought it might be trapped gas and we have given her gasx,pepcid, probiotic powder on her food(Pinnacle duck and potato), yogurt, pumpkin, an obstacle in her food dish to slow down eating. Nothing has helped.She has had this sporadically in the past but much less intense and only lasted one or two nights.Vet could not find anything wrong although she had been to him several times and even had a barium test which showed nothing. Please advise..I can't go through another night of seeing her in so much distress and I don't want to keep giving her pain meds without knowing the source of the problem. I would REALLY appreciate any suggestions/remedies!!! Thanks!