I have recently discovered a pea sized knot inside my penis about midway in it's length. Under normal circumstances, it is not painful and you have to squeeze it pretty hard to detect it. However, when I have an erection or have sex it really really hurts. I have no pain during urination, or any problems urinating. No discharge, ejaculation is normal. I had someone mention on another site that it could possibly varicose veins tying themselves up in knots, but I just dont know. This came up on pretty short notice, just like it was not there one day and was there the next. I have sex pretty regularly, usually 5 times a week. I dont think it is any kind of STD i checked this.