Suggest Remedy For Persistent Knee Pain

i wiegh 240 lbs... im athletic and muscular. but with body fat at 25 % . ive had 3 acl and 1 meniscus rapair. why do my knees always hurt and is there a way to ease the pain.

durring activity - first 10 mins its still and not a lot of range of motion. next 50 mins im fine feel great . after i stop - immediately it stiffens up and pain starts. ... hard to walk.