Hi well come to HCM.
Your past diseases and treatment has nothing to do with what you complain.
From your story its apparent that you are masturbating regularly so urge for the
sex is there.In 90 or even more than that persons impotance is psychological, due to
lack of knolwledge and false technique.remove your anxiety
it seems from the history
that you are normal sexually.Get help of psychiatrist
who will help you alot. Thanks