About once every few days for the last decade or more, when i sneeze, i get a real painful cramp for about 7 seconds in the area at the bottom of my scrotum or near the vas deferens i guess.

Possible hernia: you should be checked for a hernia with an exam and ultra sound if necessary

Pudendal Nerve: This is the main nerve of the perineum, the area you are describing. It supplies innervation to the region in both males and females. Many functions in both. Try standing up when you expect this and tighten the muscles in that area. Often this will help. If concerned, see your MD for evaluation and referral as needed. Good Luck.

Inguinal hernia: In men, an inguinal hernia may extend down into the scrotum and cause some pain when sneezing and coughing. See your PCP for consultation.