bike position / murt ?

hi all,

i just read the post in the "news" section that murt is doing tune ups for the bikes.

my problem is that whenever i go out for long cycle, say around 50 mins+ i start getting lower back pains and i think this may be due to the distance between saddle and bars and the heights of saddle and bars.

i have gone poking around with it myself but i have not got any relief from the pains so far so im wondering if i may be on the wrong track.

any ideas on what i could try or is a trip to murt the way to go to remedy this problem?

thanks!

ross