Testicle Pain With Swelling......

well i used to work for a company in which heavy lifting was required. thats around the time i felt the pain start (which was about 6 years ago). i immediately had it checked and had an ultrasound performed on my testicle. they had told me that everything was fine. coincidentally this is happening to the testicle that hangs lower and is larger than the other. the pain comes and goes and is usually very mild. any ideas?

thanx