Can a neck ct scan with contrast cause thyroid cancer in the future? ive read that the thyroid is very sensitive to radiation, and i am a relatively young (31) female?

I wouldn't loose sleep over a standard scan. Decades ago docs tried using radiation to cure bad acne & years later the thyroid sensitivity & potential for cancer was noted. The scans of today don't carry the same risk.

The added risk, if any, would not be measurable over your baseline risk. You can reduce your risk of cancer by adopting healthy habits: Eat a mostly vegetarian diet, avoid alcohol, tobacco and street drugs, avoid excessive exposure to sun, get HPV vaccine, exercise 30 minutes each day, drink enough water so your urine is mostly colorless.