What Causes Pain In Testicles After Masturbation?

Hi I am 25 years... My left testise was painting for a month. I got scared and got checked by the doctor after suffering for a month and the doctor asked me to do the ultra sound scan for testise, blood check up, urine check up and the kidney scan. The ultra sound scan for testise was normal so no issues with that, but with the blood report and urine check up it says the uric acidis more and in the kidney scan it showed there are stones in my both the kidneys. So doctor asked me to take the tablets for the stone reduction and the uric acid reduction. I took tablets and drank lot of water for three months and the stones and uric acid cured. Now the issue is different, my left same testis some time not all the time pains and the worst part is after I mastribute my left testis pains like hell the next morning it will be fine Don t know the reason... Please tell me what exactly the issue is ? But I mastribute once or twice in a week.. That s it