What Could Be Causing Mild Pain In Both Testicles, Especially During Masturbation?

Hi , 15 days ago while sleeping i stopped urine to come out . From that day i feel little pain on my both testis . While masturbation also I feel little pain . Pain is not that much and I don t fell pain while peeing . only when I masturbation there was little pain on both testis . I feel little little pain on boths sides