nervous dog

Question
Hi Ailigh,I have a problem with my 3 yr old dog,Any help would be greatly appreciated.Hes always been nervous or shy with things,But ive never had any trouble getting him to go for walks(probably cos he loves them,Untill recently.One morning last week on our usual route there was a massive bang(louder than a firework)very close to us and he was very shook up by this.So that night when i tried to walk him he stopped and wouldnt continue as soon as he realised he was going in the same direction as the bang,So i went the opposite way and he came willingly.Now he would only walk the opposite way to the bang,and be okay,But lately he has froze and refused to go on as soon as we get out and he hears the slightest thing,It could even be somebody talking normally,He shakes and cowers and im lucky if he walks further than the end of the street.On top of all that he will still come bouncing around me when he knows its time for his walks(usually two a day),Even though his walks last 2 mins,Im stumped as to what to do to relax him,He is so nervousAny help would be great,Thanks in advance for your time.

Answer
Jonathan -
What kind of training have you done with your dog?  If he is clicker trained then I would suggest a click and treat as he steps out the door and every so often as you are walking.  Dogs have a crazy ability to generalize especially if we react in a way that seems normal to humans.  Make sure you don't "comfort" him if he gets scared.  The "don't worry", "it will be Ok" only heightens nerves in dogs and it is much better to ignore the nervous dog while treating a positive response.  I would also suggest a "click and treat" approach  to any noise that is bothering him.  Basically, ignore the cowering and treat him when he isn't cowering, especially while on walks.
If you don't clicker train there are some great articles on the Web or the basic idea (without a clicker) is to click or say a work (Good) when he does something right then give him a treat.  
You can also distract him when he is nervous by asking for a series on known behaviors like sit and down which are easy and offer lots of rewards.