Suggest Remedy For Stiffness And Shooting Pain In Leg

I am male, 62 years, 168 cm ht., weight 82 kg. Had a heart attack 15 months back, had one stent inserted. Has back pain ever since. Still following mostly sedentary work sitting before PC 9-11 hrs every day. My problem now-a-days, while lying in bed, some times when I turn, my legs become stiff with some deformity, I have shooting pains in leg bones, mainly below the knee, and then I am unable to even turn back because of the pain. Changing position does not help, after sometime some how the pain goes away. It used to be infrequent, but recently the frequency has increased, happening sometimes two or three times during a single night