there can be many reasons but it would not be possible for me or any medical provider to be able to specifically determine that cause you your testicle pain blindly over the internet. you will need to see your primary care medical provider or a urologist.
i have pain in both testicles and the left testicle is kind of swollen. i thought std's but test came back normal. i also have been having pain during urination and lower abdominal pain? and like i said my urine test for std's came back clean. what could be the problem? kidney stones? ive been having slight pain around that area every so often