Pain in the testicle can be caused by many things and cannot be diagnosed over the internet. You have to go to the doctor to rule out anything dangerous, as well as get treated. Minor things such as infection can get worse, so go to the doctor.

It could be epididymitis since you mention that, which is an infection. It could also be varicocele, which is a varicose vein of the testicle. It's quite common and does usually happen on the left side, but for most men it is asymptomatic. It may account for feeling more tubes as veins are larger, or I'm not sure, perhaps more numerous.

I'm not sure why most pain appears in the left testicle, though perhaps it is because of the nature of the circulatory system and the heart. I believe that is why most varicoceles happen on the left side.

Either way, it's something a doctor should be seen about. And considering you've started many threads about recent problems, you have more than one reason to go. This website isn't to diagnose people, it's to offer help and guidance.