Thanks for your query Based on the fact that you stated and the previous history of spermatocele
being operated it could be either recurrence of spermatocele or may be a simple epididymal cyst
.However final diagnosis can be confirmed only on clinical examination and ultrasound
scanning study.The loss of erection could be due to pain and anxiety This will be settled once his present problem of lump gets cured.Consult some Urologist
for examination and evaluation.