Size of my right testicle is very very small compared to my left one although it doesn't give any kind of pain but still i think it's very small compared to the other one is this any medical condition that needs treatment?

Hypogonadism can be diagnosed by exam, specifically testicular size and secondary sexual characteristics, hormone tests, and imaging. Symptoms would have included delay in puberty (low muscle mass, no deep voice, no hair distribution), and in adulthood ED, infertility, breast tissue, fatigue, low libido, difficulty concentrating, and hot flashes.

It is possible that you had some unknow injury to it in infancy /childhood. If it does not bother you it does not require any treatment dont worry. If it does pl see a Urologist and get checked out. Good luck