On-going hamstring/buttock/lower back pain

Hi,

Some years ago I pulled the top of my hamstring i presume from doing weights and/or not stretching enough before and after.

It seemed to disappear so I felt all was ok. Now for the last 18 months or so, about every month, it comes back and i can't seem to get rid of it no matter how much stretching i do.

It could send real quick shooting pains around the right buttock region, then after sitting down for a while, for no reason be the left buttock/hamstring instead with no pain felt to the right hamstring any more.

More recently, i am experiencing really bad lower back pain during the night whilst sleeping.

I cannot reach my toes on standing hamstring stretches, and my hamstring movements are extremely limited.

I could be fine for a few days then i walk to the shops and back with some heavy shopping - and the pain returns.

I have to do something about this now as I can't remember the last time i had a pain free sleep.

Any advice!???