Hi. A very good question. First of all remember your habit of masturbation has nothing to do with your present problem. Secondly: the left sided testis is always at a lower position then the right in all males. This is natural. But in your case this is more than normal. This is due to the vein draining up in abdomen has no valve so the back pressure of the column of blood slowly dilate the veins in the scrotum. This is called varicocele and is common on left side. The increased weight causes dragging pain in lower abdomen. Please consult a Urologist to have a clinical examination and ultrasonography and color doppler examination to decide the the grade of the varicocele. Also you have to undergo semen analysis. This will guide the further treatment. You can have a scrotal support. There is no medical treatment for such a condition... The left side body being thicker than the right is a different problem. For this you have to consult the Neurologist for careful examination and evaluation.