finding out just why your hamstrings feel so overly tightened in you would help. this could be "just' some type of muscle issue or it could also be a result of over stimulation stemming from a possible spinal issue too kind of thing? there just are many different reasons why any given muscle or muscle group would 'tighten up' on us. but the very basis is usually from some type of inflammed signals being sent to the muscle/fascia that just reacts by overly thinining itself and then contracting around muscle.
i can tell you about you a great possible therepy that works directly at the base of what is the over tightening? its called myofascial release therepy? this just releases that outter fascia. it IS the outter covering that just surrounds every muscle, organ and blood vessel we just have in our bodies that when stimulated or inflammed, gets thinned and then will overly tighten around the inflammed area. that IS what is at the base part of the actual muscle crap. but finding out what just is sending the signals and causing this(and where this is coming from) would really be ideal in order to hit the true base of the problem. even obtaining a lumbar or full spinal MRI could possibly show what is going on within that spinal area that would be the most common or likely area to send out the signals to the muscles. believe me, certain findings like even bone spurring within that spine at the right level can create alot of pain and muscle issues to have to deal with.
this therepy for me has been a true godsend and the ONLY therepy i have tried out of many since my muscle damage occured from a spinal cord surgery where they had to go in the upper back just dessimated all the thick heavy muscle up there that actually works. but i would really try and get that full spinal MRI considering the symptoms are in your legs. this can come from almost any level of the spine and not 'just' the lower. it all depends upon just what the underlying generator actually is?
do your legs feel at all 'spastic/over reactive"? or is this 'just' what feels like overly tightened muscle? getting a good neuro exam by your doc would really help to narrow down the possible area of involvement. and of course that MRI too if at all possible. this would just give that better 'inside' look at the possible cause within that spinal somewhere. hopefully this is just overly strained muscle with no other real triggers there. but i would want to find out if i were you. please let me know what you find out,K? good luck, FB