Thanks for your query Based on the facts that you have posted it appears that you have sustained injury to your left testicle a6 yrs back and had surgery for Varicocele
5 yrs ago You have no issue regarding sexual life except the fact that your left testicle is smaller than Rt testicle.
Please consult qualified Urologist
for clinical examination and get Ultrasound
scanning and colour Doppler study of the scrotum and semen analysis
done to asses the function of the testicles.It should not affect your fertility.as your Rt testicle is normal