@-independentbiker... YOur testicles do not need to get hard, they will drop or raise depending of your body temperature. If too hot they will lower, or if cold they will rise back up and attach closer to your body to maintain propper temperature and maintain sperm alive. Too much heat or cold can damage your sperm count and quality.
About getting hard, You must see a doctor because there are many health conditions that may cause you to have erectile disfunction (ED). it can be hormone imbalance, cardiovascular disorder, up tissue damage on your penis or hernia. The conditions are numerous but can not be certain until you have been diagnosed by a proffesional Medical Doctor or a specialist.