If you're doing stretching, could you describe your grip technique, how tightly you're gripping, how much tension you're using to stretch? Same with the jelq.
Can definitely advise you never use shampoo as a lubricant. Shampoo can be very irritating to sensitive skin (eg your glans/foreskin). If you're beating up those sensitive areas (or even using perfect technique), you want to use a legit genital lubricant. You also have to take care of the skin with routine moisturizer/emollient.
If you're injured, take a break, heal back to baseline, go back at it with better technique/less intensity and a better skin care regimen. Get the grip/tension dialed in by starting low and slow.