Bike adjustments and strengthening tips are generalizations, and may not work for your individual needs. If you have tried the above suggestions without success or want an individualized fit, you would benefit from a professional bike fitting. The fitting I perform is both a static and dynamic bike fit, where static measurements and adjustments are combined with a dynamic movement analysis and orthopedic examination. A proper bike fit is a marriage between the bike and the rider, so one needs to look at both the bike and the person when performing a bike fit. Getting a professional bike fit can significantly reduce pain associated with your riding, reduce the chances of developing future overuse injuries, and perhaps, best of all improve, your performance.
Resources:
http://www.serottacyclinginstitute.com/BikeFitBasics.html
http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO&INTRO_LINK=NOREDIR
http://velonews.competitor.com/tag/bike-fit