Leg pain, which specialist to visit?

Hi, my name is Nabin Kumar Sharma, my age 32, my weight 74 kg, my height:5 fee, 9 inch. l have been suffering from Leg pain from some times now, it's like if a take even if l take a walk for 500 meter also. ln brief: The area below both of my knees will pain. The pain will be there. I have been suffering from this for more than last 2 years and have not done any major treatment for it, as the pain is increasing its time l have decided to get it checked. Notes* Sometimes while l am asleep, in my leg, the area behind the knee (nerves) gets is round in shape, nerves will pain, blood circulation stops for a moment and it awakes me, l feel severe pain and can't even touch the portion, last time it happened was some 1-2 months back, due to tht for the next 24 hours I will pain in my same leg. l am looking forward for help on this. l will Will prefer to visit the clinic with the correct specialist and get correct treatment for this. May l know which specialist to visit? thanks for the help.