I had kidney stones last summer and for the past 3 days i've had severe cramping but on opposite side. i started working out 2 weeks ago. is that why?

Maybe, ...or not: May be muscle spasm etc., but ...Kidney stones can come back, especially if dehydrated, not following diet changes, e.g. Low oxalate, meds to alter urine ph, etc.. Stones can be on either side, or both. Symptoms if passing, none if in neutral corner. Best way to prevent stones... Fluids, fluids, fluids. Either way may have blood (visible grossly or microscopic) see your doc.

See your physician: There are many reasons why you have a kidney stone. If you had a kidney stone, it would be good to find out if it was a calcium or uric acid stone in order to lower the calcium or uric acid levels. There are many causes of severe abdominal cramping. See your physician. The most severe would be messenteric ischemia. It would be good to have a good history and physical to determine your problem.