Hi. Thanks for your specific history that you are getting pain in the testicles whenever you have a long run or a walk. Taking Addrall may not have any bearing in the pain of the testicles. The most probable reason that you are getting vasocontrictive like symptoms and there is tightening of the sac itself indicates that there is contraction of the lower abdominal muscles causing retraction of the testes by action of attached cremaster muscle and thus causing partial torsion giving you such a pain. The treatment first of all, is obviously stop lone runs or walks. Secondly get clinical examination done by a General Surgeon or Urologist to see what exactly is a problem and to get operated accordingly to avoid this in future.