Your query isnt very clear. I assume you mean you have 1 testis.
If this is the case, you must seek a urologist ASAP as the other testes may be in tummy and it will be not functional. But these tummy testis needs to be removed as chemicals from there can harm the normal situated testis.
Next Steps
meet a urologist. get evaluated about your testis and urinary problem
Health Tips
1-testis is enough to lead a normal life and have normal sex life. If you are having erection and good hair on beard, armpit, body it means
testosterone levels, produced by testis are ok..
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do a semen test from reputed lab after ONLY 4 days of no sex or masturbation. see this report and if sperm levels are ok, it means every is fine. just get rid of that testes thats in tummy, if it is