Got u/s done and nurse said no bloodflow in lump on top of right testicle on epididymis most likely cyst or something else? is no bloodflow good?

In this case yes.: US is used to help determine if a mass is a cancer or something less concerning. Cancer begins initially when cells stop communicating with their neighbors and start to grow faster then the rest. Before developing into a cancer the growing mass must be able to recruit blood vessels otherwise it cannot progress. Regular, smooth shape, freely mobile are all good signs if present.