Maybe the fear comes from fighting against someone who is good at countering. If EVERY punch you threw had your opponent moving & sticking a hard jab into your chin before yours has even landed, sooner or later your going to start thinking it's not a good idea to be punching this guy. even 'afraid'..... If this is the case, you could try to become an expert counterer yourself. Just hold back and let him make the moves & whop him as soon as he overcommits to any punches.. Your fear of throwing the punches will turn into an itching to throw them... And itching for your opponent to show you that smallest gap that you can unload on...

All fears spring from something or somewhere. Analize where yours is coming from, and turn it around into one of your strengths... Nothing helps your motivation & confidence when something you were once your weakest at, is now one of your biggest strengths... It makes you feel unstoppable..