Have large mass on uterus,small one on left ovary,does that mean i have to have a hysterectomy?

Not necessarily.: Unless the masses are malignant(cancer) or are causing other problems that cannot be cured by removal of the masses alone.

NO: If the mass is stable and less than 12-14 week size, as with a fibroid, and you are not having any symptoms due to it, then it could be observed. If it is a problem then the mass itself may be amenable to removal without a hysterectomy. You doctor should be able to give you the correct guidance.