profsuzy - I had the same pain for years, though it would not happen until after about 40 miles. Also rode a Lemond though it was not the bicycle's fault. My top tube was too long & even after swapping out for a shorter stem & moving the saddle forward as far as possible, it did not stop completely. I hope this is not your issue! Do you trust the fit your LBS gave you? I did....but they were not as experienced as I assumed. Good luck!
"When I'm on my bike I forget about things like age. I just have fun." Kathy Sessler
2006 Independent Fabrication Custom Ti Crown Jewel (Road, though she has been known to go just about anywhere)/Specialized Jett