My obgyn says I have a large cyst on my fallopian tube that has other little growths inside. Can I live with this or do I need surgery? Says its benign.

Depends. Sounds like you are talking about hydrosalpinx? Need for surgery depends if you have symptoms of not, your age, whether you are trying to get pregnant or not, and also on the size of the cyst. You should have more than one ultrasound to watch for change over time. Depending on your full situation there are also blood tests that might be indicated which can screen for chances of cancer.
Large cyst. Make sure you see a doctor. The dimension of the cyst and those little growths will determine if you need it removed now or later. Any simple cyst more than 8 CM in premenopausal should be removed( risk of ovarian torsion) any cyst with unusual growth inside should be adressed with repeat ultrasound and some blood work.