I have been off the injection for birth control 2months and have really bad stomach cramp on and off for 5 days and its not period pains what is it?

Several things: If you mean it's been two months since you were due for an injection, you could be pregnant. If you've not had a period since stopping the injection, it could be premenstrual. You could also have an ovarian cyst. I'd recommend seeing a doctor soon to have it evaluated. If the pain is severe, i would recommend a visit to the er.