Sir now it's almost 4 months after my hydrocele surgery still my right testicle (operated side) is bigger and hard to touch as compare to left testicle.is it normal ?

At 4mo - this really should not be the case. I would suggest that you return to see the surgeon again.

During hydrocele surgery the fluid around the testicle is removed and the sac containing the fluid is accordion/overlapped to prevent recurrence of the fluid sac. The larger the sac, the more tissue is tucked behind the testicle giving it a hard texture. It can take up to a year to soften but the fluid should not return. Your surgeon can order a sonogram to determine either.