There are many causes of pain in the testicle. Since the duration is relatively very short (only 2 days), pain apparently not severe, and physical examination negative, don't get scared at the moment. It will be prudent to observe the problem for ~ 4-5 days more during which see if new additional symptoms develop and/or intensity of pain worsens, in which case ultrasound
scan examination of the abdomen (including kidney
) + scrotum
may be appropriate.