Hi ! There are two possibilities which can be drawn from your history without a proper clinical examination :
1) Epididymo orchitis
, with increased blood flow in the epididymis
shown in the colour doppler. In this case pain may be there and a proper scrotal support, antibiotics and anti inflammatory drugs with proper rest may solve the problem.
2) Vericocele ( dilated veins ) of the testis. This is a also a benign condition but may require a semen analysis
initially as it is said to cause infertility
. In that case your urologist
may advise to undergo a surgical procedure.
Wishing you an early recovery.