dog pulling always on leash

Question
I have a 'used' German Shorthair Pointer...I am at least the 3rd owner and she is only about a year old.  I have run after the ball in my yard until she seems,,,,tired but when I try to walk her she is walking me and it really hurts my back.  Should I use a regular collar or some sort of harness.  I have a Haltie but naturally she is not crazy about that thing at all.  She is just your typical high strung GSP and young too but I am quite conserned about her straining on the leash - my poor back not withstanding.

Answer
I'm including some information on loose-leash walking.

There is a product called the Easy Walk No Pull Harness that a lot of people have good success with.  You can do a search on the Internet to find a store that sells it.

Some people may suggest a "prong" or "pinch" collar- these have some degree of success, but they should be fitted correctly in order to work properly and they need to be USED correctly as well.

http://www.marinhumanesociety.org/Behavior/Handouts/LLW.pdf