Hello when i was 12 years old i had a testicular torsion which make me remove one testicle at that time. now i am 17 and i want to lift some weight and excercise in gym everyday is there any problem?

When you have testicular torsion surgery then you need to avoid strenous exercise or weight lifting for several weeks. It has been 5 years since your surgery therefore weight lifting and exercise should be fine. However, some people can get testicular torsion a second time but on the other side. You need to see if at the surgery they attached the remaining testicle to prevent this from happening.