Should I Be Worried If Dull Testicular And Left Buttock Pain Persists Despite Two Rounds Of Antibiotics?

Hello, For about the past 4 weeks I have had a dull ache in my testicles and pain in my left bum cheek too. The pain is not constant but it comes and goes. I have been to the doctors and he said I have just got an infection and that’s it’s nothing to worry about. I was given antibiotics however the first batch didn’t solve the issue completely and I am currently taking a second dosage. However, I’m not convinced these are getting rid of the issue either as I have been taking them for about a week and the pain doesn’t seem to be going away. I am 18 years old and am not sexually active too. I have a scan booked in for early June just as a precautionary measure. Should I be concerned about this? Thank you.