My son had testicular torsion surgery 3 weeks ago. i have just taken him to specialist with a new concern and specialist advises he now has testicle varicocele. could this new condition be a result of the torsion surgery?

Likely unrelated. A varicocoel is somewhat like the dilated veins in the legs a woman acquires after pregnancies. It is not uncommon in males & considered a simple defect that does not become evident until the teen years. Torsion surgery is an emergency procedure that just unwinds a testis that twists on its stalk compromising its blood supply. The testis is then anchored in place.