Thanks for posting your query.
You are most likely suffering from acute onset epididymo-orchitis
with testicular feeling in lower abdomen.
Presence of tender testicles along with pain suggests the diagnosis.
You should consult with internal medicine specialist/ general surgeon
and should go for thorough check up.
You should also go ultrasound
imaging of testicles along with kidney.
Epididymo-orchitis is due to infection either viral/ bacterial.
Mumps infection is also a common cause of this infection.
You should also go for urine analysis to rule out any infection.
You should take proper antibiotic
along with analgesic for relief of pain.
Dr. Mayank Bhargava