Hi.
When was your surgery done?
If you only had a recent testicular surgery done then the pain is likely associated with the surgical procedure and this may require antibiotics and pain relievers. Based on your ultrasound findings there seems to be no involvement of the epididymitis which may help us rule out infections of nearby structures.
At this point, I suggest that you continue to observe your symptoms. In the presence of severe pain, redness and swelling , an immediate consult will be necessary.
Has the surgical incision healed already?