36 pregnant of twins and having tightness in my stomach with pain should i call the doctor?

Yes: The average age for delivery with twins is 36weeks this could be the start of your labor. Call your doctor to let them know and get a plan.

36 wk pregnant pain: Yes. Just to be reassured if nothing else. But first need to be evaluated. Yes call your doctors office, to discuss further; more questions like vomitting or fever or vaginal spotting/ bleeding.Good luck.