Hi!
Usually the right testicle is smaller than left and in some men the reverse may be true. Sometimes a testicle may swell due to hydrocele or inflammation or infection. It can also appear enlarged due to surrounding varicoceles. So, if there is an appreciable variation in size, please re-consult your doctor. Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.