I've never been much of a bicyclist, but recently I finally broke down and bought a new road bicycle (Specialized Allez model). The sales tech sized me with the bike, made a few adjustments at time of sale. I did not spring for the $125 fitting where all the micro-adjustments are made to the bike and me.
This weekend I competed in a short sprint triathlon, my first since buying the bike. On the 5k run portion (which follows biking) I had incredible lower back pain, right in the curve above my glutes. The pain was intolerable when I jogged, so I ended up walking over half the run leg. The pain subsided with time and I finished the race. I have no history of any back problems.
My question: Is this a training problem where I need to get busy with some exercises to strengthen my lower back, or are there adjustments that need to be made to the bike? Is this a common problem when acclimating to a new bike?
I should add that I'm a 51 year old male.