hi i had gone through your query and understand your concerns. i would come up with the possibility of SCIATICA
may be the cause for your sufferings.
-exposure to damp
-pressure on nerve,by tumor,or constipation
,or through injury
-over use of limbs walking
or gout are the possible cause.
x-ray or MRI scan for lumbosacral spine,
for serum uric acid levels etc may confirm the diagnosis
I hope this is helpful for you, thank you