I face erection problem from six months, If I stop masturbation for 9-10 days I get some good erection and also get some morning erection but after masturbation it suddenly gone. After masturbation I also had some pain in my leg knees and lower leg. Is any tissue damage or something else I can not understand. During foreplay I stretch my whole body very tightly to stop ejaculation, thats my problem started day. After that stretching I got huge pain in my legs, and after 5-6 masturbation I also face erection problem. Some time when I sexually stimulated I get good erection but when I masturbated I can not get erection. I think some tissue or muscles damage after that stretching. So please help me or tell me 'how can I diagnose my problem. Why my morning erection go away after masturbation.