Pain in left testicle when not masturbating for more than 3 days

I'm a 20year old, and I've been experiencing this problem 2-3years ago. I've this kind of pain which i get particularly on my left testicles which radiates to my abdomen though sometimes on both sides whenever i do not masturbate for more than 3 days. For example, this will occur quite consistently on every 4th/5th day after i last masturbate. Its rather hard 2 describe the pain but i would say it felt like the pain u get whenever u got knock in yr testicles hard by a football or something. The pain will last between 1-3hrs and its relieved by lying down, and of course masturbating prior to the pain help relieve the pain faster (less than an hour). I'm always guessing that its due to some blood flow or whatsoever similar and dismissed it until recently since the past few mths, i noticed that my left testicle seem to hang very much lower than my right testicles as compare to before.However, during colder days when my testicles ascends, it will seem normal. Anybody with any experience or advice on this beside seeing a doctor...
Thx in advance