In reply to sugy: i would suggest a chiropractor to look at alignment, i get subluxation on in my lower back, tight hip flexor on the same side and tight bum cheak on the same side, tight SI joint on the opposite side. Also see a good physio to look at strengthening and stretching
but the best thing i've done to prevent having to go back to either the physio or the chiro is to do core stability exercises about three times a week (often more.. at my worse in terms on misalignment i was doing core every day .. soemtimes twice a day but very easy stuff until i built up to harder exercises.. my abs have always been very strong.. lower back not that strong, but much better now)
the orher thing i do is intebse self massage, i used a hard ball (like a tennis ball or even sometimes a cricket ball) in my buttock, pain ful but it doesn't have release the tension, i do this before i stretch... and it's cheaper than going to a physio for tjem to push my bum cheak with their elbow and then chrage tou 30 quid for it
insoles is also an important factor, crucial i'd say, it has helped with pretty much all my symptoms
the fourth thing (think it's the fourth preventative thing anyway
) ... i think climbing really helps with core stability, maybe bakc off on intense bouldering sessions until things really settle down but do more route climbing... i think it's brilliant for core strength, stretching etc.